Friend's betrayal. Help?

I had this friend whom I thought was my world. I confided in her and asked for her help on relationships and stuff. Then who knows why she got jealous of me and wrote really horrible things about me on her blog. One day she walked out on me and my friends. I was really hurt and angry. should I let this "friend" of mine go, or should I pretend that nothing has happened and accept the way she is?