Could you talk to a teacher at school or a counselor? Tell them exactly what is happening. Do you have a good friend who's parent you could talk to? Can you lock yourself in your room to keep you mom away from you when she is being abusive?

I'm so sorry that you are having to experience this. Please ask for help IRL. Those of us here are happy to give you support and the advice we can, but there is only so much we can do on line. Please let us know how it is going. I went through a similar thing with counting down the years until I was 18. Please get help now if you can. I didn't and regret it. Remember that you are strong and what your mom says is about her, not about you.