Help friend !!!!!!!!!!!?

I need your advice on my friend sam. we have been friends for ages, but I really want to brake up with her. the trouble is I am scared of what she will do. In some ways its grate having a friend like tulip she is exciting and different! but she is taking more and more risks, she is going to get into serious trouble try to protect her, but she can be really horrible to me calling me names and bulling me. I do fell sorry for her, because she gets treated so badly at home really think she is capable of doing something mad or bad. I can’t talk to my parents, and I have no other friends please tell me what I should do