Can’t take my mother anymore

I am 17 years old and me and my mom used to get into it a lot. We don’t get into it much lately, now my mom gets into it with her husband. He cheats on her when things do not go his way. She will vent to me and I’m not supposed to feel a way about it or I’ll get in trouble if I’m rude to him. (He’s my stepdad) Today I had a doctors appointment to get birth control and ever since we woke up, my mom been kinda whatever acting to me. I ask for help with my hair, she can’t help. She says for me to b quiet when I get ready but then starts pounding on my door when it’s time to leave. I ask to use the bathroom really quickly and she’s like No and pointing her finger in my face and I’m confused, like what is she mad for? We get into the car and she starts going on about how I have her mascara and mines. I’m telling her that if I have both its on accident but the one u want is the one that’s mine. Then she starts getting all mad about how I always wanna argue. I then tell her to just take the one I have then, I don’t wanna argue. She gets super mad bc I don’t wanna argue and starts talking about how she’s not even mad about the mascara and to just keep both. I’m like mom it’s fine have both it’s not that serious. Then she starts getting all mad like that’s not the point that’s not y I’m mad. U r disrespectful. Like what? I told her if I’m being disrespectful I’m sorry and it’s not what I’m trying to do and she gets mad Cos I keep tryna just stop the arguing. I never think u should b disrespectful to ur mom at any age, but I am a little older so I am going to defend myself when I really believe I didn’t take her stuff. She starts saying how disrespectful I am lately and I’m a problem n the house. I ask her to state the last time I’ve been disrespectful and she’s just like shut up your so ugly, your attitude is so ugly. And I start crying, it’s so frustrating with her. I turn 18 in two months and I want to leave but she won’t let me get a job to even leave. She calls me weak for crying and I can’t take it. I’m trying to wipe my tears before I go into the hospital and she’s like omg your so dramatic and I just walk out the car crying while it’s moving. Maybe I am dramatic but I just feel like a prisoner with her, having no choice but to depend on her...