[ Friends ] Open Question : Having a hard time getting over a "Friend" betrayal...?

I had what I thought was a friend, betray me. I foolishly told her personal things, she told me she understood, she loved me and I was her best friend...I found out later that she was stabbing me in the back to my boss...I've tried to be the bigger person, I am her superior at work, but its very difficult for me to even look at her anymore. I saw her crying in the breakroom today and all I could thing of was,,,"How's it feel?"... I'm having a tough time getting over it...