I got fired and I need my job back. Please help me write an apology letter!

I'm 34 weeks pregnant and I need this job. I've worked at this nursing home for two years and I have great benefits. I'm a CNA and we were really understaffed today. The nurse manager was not helpful at all and instead of getting off her ass and helping, she was sitting at a chair in her office on the phone!

I got mad at her and yelled at her for being a lazy ass. I told her to get off her ass and stop acting like she is better than us because she probably can't even wipe an ass. In my defense though I didn't know she had accommodations to sit. I also didn't know she was calling staff trying to find someone to come in.

She told me it's in her work accommodation but I'm a hot head and I was so mad I wasn't thinking clearly. I said a lot of things I'm not proud of now that I know she legitimately does have accommodations. I just didn't know that it was possible for a nurse to be like ... disabled and not be doing nurse things.

I need this job back. I HAVE to have this job! Without it, I can't afford my bills. I can't take longer than a couple weeks off after my baby is born.

I feel like if I write something heartfelt I have a chance of getting it back. Please please please help me. The nurse I yelled at has fibromyalgia and endometriosis if that helps. She also has something that makes standing for longer than like an hour difficult which is why she's in management and not on the floor like us.

I do honestly feel bad but like... I'm pregnant and emotional so give me some grace too.

EDIT: I went to the union and I'm going to see if they can help me. I'm hoping they have some compassion for a pregnant lady. It might come down to a he said she said situation but honestly I have no problem doing whatever I need to to get my job back at this point.

EDIT 2: I got an email back from my union rep and they said that there's nothing they can do. I violated the code of conduct and being pregnant does not protect me. They said that they will investigate it further but suggested I let it go. I'm going to file a grievance about how it was handled because I think I should have had a warning or some type of progressive discipline. To get fired for a minor lapse in judgement isn't right.