My best friend (whom I've known for 15 years believe it or not) betrayed me?

She betrayed me big time, we've known each other for years and I've helped her and I've been with her through both joyous and sad times and yet she hurt me so much. I cannot face her anymore 'cause she won't let me, she knows what she did to me and so she's not going to show her face anymore. I just want to forget her and move on with my life but how? She has been in my life and now my life seems empty, like I've wasted 15 years of my life, that's exactly how I feel right now. I want to erase her from my mind. I'm 17 now and do things like these even happen? Losing someone you have known for your whole life? I can't take it anymore :(