AITA for confronting my roommate?

So I 23f have a roommate, Gwen 19f, and we share an apartment. Gwen works night shifts at CVS, from 10pm to 6am. She typically gets home around 6:30am. On days I work, I have to get up at 7am. I have a really bad issue of sleeping through alarms, so she gets me up at 7 on days I work so that I don't oversleep. I don't set my alarm anymore because she works Tuesday-Saturday and I work Wednesday-Saturday, so she's always available to get me up at 7am. She knows I don't set an alarm.

Anyway, a few days ago she did not wake me up and I ended up sleeping in until 8am. I was extremely late to work because of this and got in trouble with my boss because of it. I was super pissed about this so I confronted her about this when I got home. She told me that her shift relief called out so she had to stay until noon and was not able to go home. I told her she could have at least called me to try to wake me up. She just kept making excuses about how she couldn't make phone calls at work, even though she could have just went to the bathroom. When I tried to explain this to her, she claimed I am "ungrateful" for her waking me up and said she won't do it anymore. I called her immature for trying to avoid her responsibility and she called me self centered. I went to my room because I was tired of the disrespectful things she was calling me.

The next morning, she was gone again when I got up for work and texted me saying she wouldn't be back until late morning because she and her brother went out to eat breakfast after she got off work. This really upset me because it felt like she was throwing in my face her lack of responsibility, so I didn't respond. When I got off work and came home I told her she is being petty and that she could at least be civil since she wants to avoid her responsibilities. She called me a horrible roommate and told me that she can't tolerate living with me anymore. We started arguing, she ended up leaving the apartment crying, and now she won't answer any of my texts or calls. I know I may have said some rude things in the heat of the moment, but I felt really disrespected by her actions and was trying to communicate that. AITA?