I believe you are thinking about getting an "emancipation" from your parents. That is, a legal separation from your parents, for good reason

In your state of South Carolina, that is next to impossible at 15 years old. Unless you plan to be a "child bride" ---and they can legally stop you there too--you must be at least 16 to file for an emancipation. Let's say you were able to file legally for that--you would need to prove you had a means of self support, which means a job, money for rent, food, medical care, etc You must prove that you have the money for these things without any money from a parent!
This legality usually works best for a young person whose parents have split and he has money enough to rent a room, has a car, and is already close to the age of majority.

Different states have different laws about this but I do know they are going to take into consideration the events that led you to this decision, whether or not you can take care and support yourself (meaning balancing school and a job and paying bills and finding a place to live that will rent to a 15 year old). Among a whole list of other things. Basically you have to prove yourself an adult. Harder than it sounds.

You can seek an emancipation order if you're just trying to go it on your own. However, if abuse is involved, you can seek an order that will sever your parents rights and place you with a foster home temporarily until you qualify for emancipation in your state. Talk to your school counselor.

You will need money, lots of money, and a lawyer.

What you are looking for is called EMANCIPATION from your mother but it does in fact have to be legally granted to you. I think the best thing would be to see if you guys could work things out with counseling if not then you can contact a Social Worker.