<human>: I've been best friends with this girl for almost two years and we were very close and open with each other but completely platonic.
Recently I started to develop feelings for her which I thought were reciprocated, until I found out one morning that she'd fucked my friend in a drunken encounter the previous night.

A bit of context: we were spending a lot of time together, probably too much. I'm at college with a small close knit group of friends, and I feel like this has alienated me from the group.

I told her my feelings and she apologised for not making her feelings clearer. She wasn't interested but still wants to be my best friend. I told her I can't do that and I've made it clear I'm avoiding her.

 I've shared this with one close female friend but I haven't told the guy yet. News around here travels very fast so everyone in my social group knows about this happening but they don't know how I feel about it. In the past I'd have shared something like this with my best friend and normally felt much better but now I can't do that.

I don't know how to move forward with this and I feel very lonely here in this claustrophobic environment.

Give me a shortened version of the text
<bot>: Get feelings for best friend, she's now fucking one of my friends semi-casually and I am struggling to deal with