I found the guy I like making out with one of my best friends. Help?

First of all let me make it clear that the girl in question did not directly know that I was interested in this guy, so I don’t really blame her for anything. Now I’ll tell you how it happened. I’ve known this guy vaugly for about 5 years but just recently really gotten to know him. He is attractive, and extremely nice and smart. While at a party with my bff and my crush, he and I were flirting quite a bit. He made a big scene about putting his number in my phone so we could “text 24 -7” and kept hugging me, playing with my hair, laying in my lap on the couch, and and stuff like that. All of a sudden, out of nowhere, his attention turned to my friend. He started obviously pushing me out of the conversation and would only address my friend. Feeling confuse and awkward, I went to get some food. When I came back, I saw him and my bff making out in a corner. I just don’t know what changed or what happened, and he definatly isn’t the player type, so I’m confused and hurt. I kind of talked to my friend about it and she said it just sort of happened and she does’t really want a relationship or anything like that. I didn’t tell her I was interested, because I didn’t want to make her feel like I was mad at her or anything. What do you think happened? Why did he change his mind? Did I read the signs wrong in the first place? Do you think I still should try to get his attention? Do I even have a chance?