Mean friend

Last week, out of the blue, my friend decided to be mean to me. I asked her what I did, and she said I didn't do anything, and that I was just annoying her for no reason. Since then, she has made derogatory remarks to whatever I say and has been flat out mean. I finally confronted her about it, and she denied being rude to me. I told her that I'd forget about what she did to me if she just wanted to be friends and forget about it, but she ignored me. When I saw her yesterday at a group event, I even tried to hug her and she backed away, saying "umm we don't hug". I couldn't believe she would do that to me, especially since she's the one being mean and should be reaching out to me. Whenever our friends ask her why she's mad, she says she doesn't have a reason, she just wants to be mean. What should I do?  I've been upset about this for a week, and she won't stop.