How should I deal with moving out when my family does not want me to?

Today I told my mother I'm moving on campus next semester instead of staying at home. We haven't had the greatest relationship in the past to the point where I'm not sure if it can really be fixed. I know I waited until about a week before I'm leaving and I realize that was a bad move, but I've been worried about telling her for months now. I explained to her in a calm manner that I'm moving because she's not being supportive of me and has said some offensive things to me in the past, but she basically denied that it was her fault and started screaming at me about how I'm making a mistake and she said quite a few hurtful things to me. Now she's saying she plans on doing whatever it takes to keep me here and that if I leave it'll cause a huge rift in our relationship, and after our discussion she told me to rethink my decision and get back to her tomorrow. I still don't plan on living at home because mentally I can't take it anymore. I love my mom, but I can't deal with the stress she causes; it's already caused me to barely be able to function and my grades slipped because I had trouble concentrating because I was always worried about my home life. My mom has threatened to kick me out before for no valid reason, and I feel that I need to have somewhere to stay in case it happens. I'm at the point where I really don't want a relationship with her and I don't know if she wants anything to do with me either. But what I'm getting at is that tomorrow I'll need to tell her I'm not staying and I'm scared about her reaction to it. I have no clue what to expect but I know it won't be pleasant. I guess I want to know how to get through it and how to tell her without getting upset, because I can't think clearly at all when she gets to me and I need to be ready for whatever might happen.