How can I leave legally if I barely turned 17?

I get close to $1000 a month and my room is just a little office. It doesn't even have a door. I really have no reason to live if I live here. My mom and her fiancé keep yelling at me for no reason. I clean the house and take care of their child and sometimes I wear dresses which is normal and my mom calls me a prostitute. My back has been hurting so much and she doesn't want to take me to a hospital or see anything. One day my brother came out of the bathroom looking a little pale and she went crazy wanting to call 911 because supposedly he was really sick. None of my brothers clean the house and when I tell her, she starts yelling at me that I'm lazy. Since my room doesn't have a door, the baby always walks in and moves my stuff or plays with my makeup and when I take her out, she starts crying. Her parents would yell at me that if I keep hitting her, they will kick me out of the room. My mom and her fiancé are in a bad relationship. They're on and off him hitting her or yelling at her or breaking things. I just can't live here.