What's going on with my close friend and crush? Does he like her?

there's this guy who i became good friends with, he would usually flirt with me and we'd pretty much message every day and we had so much in common and got along very well. i feel like he maybe had feelings for me but i slowly developed the feels. only about 3 weeks ago was when i discovered i do in fact like him and i told my close friend that i like him. she got really excited and said that everyone thought we were compatible. It's really weird because the week i told her i liked him was the week he became distant with me. I feel like he likes her now. the past 3 weeks he hasn't messaged me at all, i would try message him and have conversations but he'd either be blunt or leave me on read. He's always messaging her now and facetiming her (every day! and i can't even get a text), they hardly ever spoke before. she flirts with him when we're in the library and moves to sit right next to him. i know it sounds childish but it really hurts watching them. she knows i like him so why is she acting oblivious. I've had crushes before but when you crush on a close friend it hits hard. i feel so **** and insecure around them and i just want to know why he's suddenly ignoring me and paying attention to my friend. I really like this guy and i think this is what heart break feels like. i've given up on messaging because he's not trying and i don't want to seem desperate but i'm really hurt. i'm okay with him not liking me but why has he cut me off all together? Any advice?