I think you went into the night with the wrong attitude man. You went in hoping to get together with this girl and as soon as you saw she might be with someone else, it tainted the whole experience. How long have you been out of high school? Have you made any effort to keep in touch with these friends? Are they all in college, in town for Thanksgiving? Maybe she really did want to reconnect with you as a friend or just get the whole old gang back together since you were all in town this weekend. If you're still in your teens or early 20s, there's plenty of time to make your life better, hell you can do that in your 30s, 40s, 50s, but it's gotta come from inside.
Best advice I can give about this particular situation, keep an open mind, from your post you didn't even seem to try and reconnect with these friends cause you were pissed your friend still didn't want to jump your bones.
