@Helpfulhelper,
Talk to your father about your wishes. You will need to work with him in order to make this happen. Most likely, everyone will have to go to court.
In the meantime, do what you can to keep yourself safe and warm, and retain your privacy, whether it's changing in the bathroom or wearing extra socks to bed or getting involved with a club or sport at school so you're out of the house. We can't help too much from here. The best people for you to be working with are your father, your doctor, and any other trusted adults, such as a teacher or a member of the clergy.
I'm so sorry this is happening.