Should I feel guilty? Please help?

I quit being friends w/my best friend b/c she always does things to let me down. We were friends for 3.5 years. She would always do whatever she wanted & expect me to still be there. (ex: she had w/a guy I really liked multiple times & bragged about it to me; she went to hang out w/a guy she liked & i was trying to get in touch w/her. she wouldn't even take one minute of her time to call me back; she would make me out to be the bad person to her parents; start crazy drama; etc). Well about a year ago I was out w/one of my friends ("Haley") for/her birthday. The guy ("Mitch") that my best friend ("Lynn") obsessed over was there too (they never dated- she just chased him around & they would have + do drugs). "Haley" & I ended up going to hang out w/him & his friends. When "Mitch" & I were by ourselves he grabbed my face & started kissing me. He apologized for it after wards. I ended up going over to his house & he played his guitar for me then he took me home. (We didn't hook up or anything.) I just told "Lynn" about it today b/c we HAVEN'T been friends since December b/c she let me down yet again. (That was the final straw). She calls/texts me every other day & b/c she won't leave me alone- I decided to tell her about "Mitch" & I. Of course when she found out she was mad, but I really feel like I did nothing wrong. It wasn't like I knew it was going to happen or did it on purpose.When I brought up how she messed around w/a guy I like she said "you only saw him a few times so it wasn't like u had dibs." My question is should I feel guilty?? I never gave him any signs or signals. I can't help it a guy she liked kissed me. She said I was a backstabber & is trying to make me feel bad. I treated that girl like gold too. :-/