Is NOBODY wrong in the post ? POST : First off, on mobile so sorry if formatting sucks. This is probably gonna be long.

As a bit of background, my fiancée and I are both trans, and we're expecting a baby in 8 weeks.

My fiancée is bipolar, and unmedicated. She blames her insurance lapsing a while back a lot of the time, but refused to actually make an appointment with a therapist despite promising to do so repeatedly.
To combat her symptoms, she decides to smoke weed. A lot. Which is legal, but she's bought $100 worth of weed in the past two weeks, when we're struggling to finish getting ready for our daughters arrival. 
Including buying from a ex-prostitute that she cheated on me with for pills while I was on bed rest due to bleeding early into the pregnancy.
I am currently not working due to medical issues, and am enrolled in a program to see if I can qualify for cash assistance to help pay our bills.

Onto today;
We went out to her friends house so she could pick up. I had to pick up new maternity pants and such for uniform requirements, so I went with her. She got mad that I had to try on clothes and snapped at me for "saying everything so loudly" when I asked what her problem was, calling me a cunt and storming off. Now, I am autistic, and sometimes have volume control problems, so maybe I was being loud. I'm not sure on that part. But she was pissed because I was taking too long trying to find fitting clothes. 
I was relieved she wasn't getting from the dealer she cheated with, but it ended up being an hour away. And we ended up having to sit there an hour and a half because he wasn't home from church yet, and wouldnt answer his phone. When he finally showed up, they went on for ten minutes and then we left for another hour ride home in the dark.
I hadnt eaten all day, which is on me, but I didn't think we would be gone all day either.
We got home, and she decided to smoke with everyone and told me to pick a movie for after, since I cant hang out while they smoke because of the baby.
And I snapped at her about how we were supposed to be cleaning today and finishing cleaning and setting up the baby's things in case she comes early, because she's promised to help me for two weeks now. So I stormed away, and immediately felt bad for snapping, and about ten minutes later apologised for snapping while she sat and looked dejected because I didn't want to watch a movie with her. I still feel bad, but am currently trying to cool off alone because I dont want the stress effecting the baby.

I really didn't mean to upset her, and I know there are things she cant help due to her bipolar, and I feel bad for snapping when I should've kept a more level head.
So what's the word, am I the asshole?