Is NOBODY wrong in the post ? POST : Clarification

My boyfriend is out of the country. We message each other daily. Yesterday night, he got home and messaged that he missed me. I messaged him back, but didn't reply for 30 min. because he was listening to some singers (he was also with his friend). For some reason, this irritated me. He uses his phone a lot and I'm assuming he just saw the notification and just swiped up to reply to me later. 

Background: Early in our relationship, he said that it bothers him when he is texting someone and they reply even a minute late. (A little unreasonable, because but whatever, that's his thing) So I try to reply to him as soon as I see the conversation. Like I'll message good morning as soon as I wake up. I noticed he has this habit of not messaging me right away even though he has this stipulation, so I talked to him about it and he said he will do it. And he has been. 

I understand he is out of the country and I try to be understanding. Usually there was something going on and I get it, he can't be on his phone 100% while he is with family/friends/etc. But yesterday, that small 30 min. seemed deliberate. 

Anyways, I tried not to let it bother me. But it was obvious it was during our video chat that night so I ended it early and said I just wanted to sleep. 

AITA? Tbh I just want confirmation that I am so that I can attribute this to anxiety and be done with it. But I sometimes overthink things and I'm curious to see what other people think 