user10831: I was meditating. I was using classical music as my object of meditation. 
I know some don't approve of that but it's REALLY relaxing, especially while meditating. Anyway, as I was meditating the music became... so much more clear. I really can't explain it. It's like I had cheap headphones and all of sudden they switched to top brand headphones. That's how clear it became. Then my breath became very shallow almost as if it was disappearing.
Now I have anxiety attacks, such as I had during my previous attempt at meditation. And that makes my breath feel shallow. But this was different I felt it slowly disappearing. And this very unusual feeling overcame me. My whole body was blissful. I never had that experience before.
So was that a Jhana state?

user2265: You did not experience jhana... you experienced pre-jhana a.k.a. ACCESS CONCENTRATION.
Keep in mind that until this (and the other factors) are stable and you do not drop out of meditation before your set period of time... you have not experienced 1st jhana.
I would also suggest to take a more stable meditation object.
Music is very changeable and erratic and having that as a concentration object is not good beginner practice. It can harm your practice.
Just chill out and watch your breath as happily as you did the classical music. :)

user6994: 
Achieving even śamatha by focusing on a sense object is impossible.

One has to concentrate on a mental image. For instance, it is said that when one achieves śamatha by focusing on the breath, he focuses on a mental image of the breath from the fourth abiding (far before śamatha itself). So, when you speak of meditating while listening to music, this is the first thing that comes to mind.

Actual bliss (Skt. prīti) does not occur before one has achieved śamatha, a mind of the form realm.

Therefore, you were not abiding in śamatha (much less the jhanas) you could not possibly experience actual bliss. You could very well have experienced a fact simile of bliss, a somewhat blissful experience. Geshe Gedun Lodro explains it well in Calm Abiding and Special Insight: Achieving Spiritual Transformation Through Meditation.

Once you achieved śamatha, achieving it again becomes easy.

This is also something to consider. If you can not experience whatever you experienced again and easily, it is a sign that it is not a jhana.

Leah Zahler wrote a comprehensive book on the topic: Study And Practice Of Meditation: Tibetan Interpretations Of The Concentrations And Formless Absorptions.

user-1: This part sounds like jhana to me: "My whole body was blissful." The fact that the music became more clear doesn't sound typical of jhana but rather one of those unusual sort of experiences that happen every now and then during meditation. 
As many are saying, it's hard to say definitively if it was jhana, but at the very least, it sounds like you're on the right track. I would encourage you to repeat whatever you did that led to that feeling (e.g. focus on whatever you were focusing on) and see if it happens again, and then continue doing it and see what happens. 
One of the purposes of jhana is to create a pleasant feeling so you enjoy keeping the mind inward and still, and since it sounds like this experience accomplished that, it's probably worth continuing with. [As a side note, if after experiencing it you feel it "slipping away," don't feel like you have to struggle to get it back. After the first-third jhanas, the mind naturally settles more into a state of equanimity as opposed to bliss and rapture.]

user8157: No, it was not jhana. Feelings of bliss are not necessarily always 'jhana'. However, the bliss arose due to the cessation of anxiety. It was not jhana bliss however it was certainly a kind of bliss. 

user295: 
Now i have anxiety attacks and at first was i was having an anxiety attack during the meditation.

This does not look like Jhana. Jhana is blissful. Sometimes you might experience Piti and Sukkha. These may be intense. 

user10950: I wouldn't worry about what it is or isn't and dont listen to what other people have to say about it either as everyone will have varying opinions and really they cannot know what you experience. You will end up feeling confused. The main thing to remember is that it was just a pleasant experience and like all experiences it arose and then passed. It's like a small reward for making progress. Try not to think about it or recreate it as it may hinder your progress. It does not need a label.
If you go into meditation expecting, hoping or craving to have the same experience again or for another pleasant experience you are missing the point so don't fall into that trap. However, when you do have a pleasant experience, enjoy it for what it is then let it go. 

10831: <p>I was meditating. I was using classical music as my object of meditation. </p>

<p>I know some don't approve of that but it's REALLY relaxing, especially while meditating. Anyway, as I was meditating the music became... so much more clear. I really can't explain it. It's like I had cheap headphones and all of sudden they switched to top brand headphones. That's how clear it became. Then my breath became very shallow almost as if it was disappearing.</p>

<p>Now I have anxiety attacks, such as I had during my previous attempt at meditation. And that makes my breath feel shallow. But this was different I felt it slowly disappearing. And this very unusual feeling overcame me. My whole body was blissful. I never had that experience before.</p>

<p>So was that a Jhana state?</p>
 2265: <p>You did not experience jhana... you experienced pre-jhana a.k.a. ACCESS CONCENTRATION.</p>

<p>Keep in mind that until this (and the other factors) are stable and you do not drop out of meditation before your set period of time... you have not experienced 1st jhana.</p>

<p>I would also suggest to take a more stable meditation object.
Music is very changeable and erratic and having that as a concentration object is not good beginner practice. It can harm your practice.</p>

<p>Just chill out and watch your breath as happily as you did the classical music. :)</p>
 6994: <ol>
<li>Achieving even śamatha by focusing on a sense object is impossible.</li>
</ol>

<p>One has to concentrate on a mental image. For instance, it is said that when one achieves śamatha by focusing on the breath, he focuses on a mental image of the breath from the fourth abiding (far before śamatha itself). So, when you speak of meditating while listening to music, this is the first thing that comes to mind.</p>

<ol start="2">
<li>Actual bliss (Skt. prīti) does not occur before one has achieved śamatha, a mind of the form realm.</li>
</ol>

<p>Therefore, you were not abiding in śamatha (much less the jhanas) you could not possibly experience actual bliss. You could very well have experienced a fact simile of bliss, a somewhat blissful experience. Geshe Gedun Lodro explains it well in <em>Calm Abiding and Special Insight: Achieving Spiritual Transformation Through Meditation</em>.</p>

<ol start="3">
<li>Once you achieved śamatha, achieving it again becomes easy.</li>
</ol>

<p>This is also something to consider. If you can not experience whatever you experienced again and easily, it is a sign that it is not a jhana.</p>

<p><br>
Leah Zahler wrote a comprehensive book on the topic: <em>Study And Practice Of Meditation: Tibetan Interpretations Of The Concentrations And Formless Absorptions.</em></p>
 -1: <p>This part sounds like jhana to me: "My whole body was blissful." The fact that the music became more clear doesn't sound typical of jhana but rather one of those unusual sort of experiences that happen every now and then during meditation. </p>

<p>As many are saying, it's hard to say definitively if it was jhana, but at the very least, it sounds like you're on the right track. I would encourage you to repeat whatever you did that led to that feeling (e.g. focus on whatever you were focusing on) and see if it happens again, and then continue doing it and see what happens. </p>

<p>One of the purposes of jhana is to create a pleasant feeling so you enjoy keeping the mind inward and still, and since it sounds like this experience accomplished that, it's probably worth continuing with. [As a side note, if after experiencing it you feel it "slipping away," don't feel like you have to struggle to get it back. After the first-third jhanas, the mind naturally settles more into a state of equanimity as opposed to bliss and rapture.]</p>
 8157: <p>No, it was not jhana. Feelings of bliss are not necessarily always 'jhana'. However, the bliss arose due to the cessation of anxiety. It was not jhana bliss however it was certainly a kind of bliss. </p>
 295: <blockquote>
  <p>Now i have anxiety attacks and at first was i was having an anxiety attack during the meditation.</p>
</blockquote>

<p>This does not look like Jhana. Jhana is blissful. Sometimes you might experience Piti and Sukkha. These may be intense. </p>
 10950: <p>I wouldn't worry about what it is or isn't and dont listen to what other people have to say about it either as everyone will have varying opinions and really they cannot know what you experience. You will end up feeling confused. The main thing to remember is that it was just a pleasant experience and like all experiences it arose and then passed. It's like a small reward for making progress. Try not to think about it or recreate it as it may hinder your progress. It does not need a label.
If you go into meditation expecting, hoping or craving to have the same experience again or for another pleasant experience you are missing the point so don't fall into that trap. However, when you do have a pleasant experience, enjoy it for what it is then let it go. </p>
