Gutted :(

Ok so theres this guy ive had a crush on for like over a year now (lets call him jim), he wud have been quite flirty with me like over msn and stuff but he had a gf so i never acted upon it. On a nite out with my friends a few weeks back we ended up chatting to him and his mates, although he came over to us, completely blanked me and started talking to my friend he barely knows :s so i thought ok fair enough and went over to talk to his friends. One told me that jim wanted to talk to me so i went over and asked him what it was about but he said he jus wanted to say 'hey' so anyway later on the same friend told me that jim rele liked me and another of his friends was sayin it too. Our mates left the two of us on our own for a bit and we were chattin away and stuff there was a moment wen we nearly kissed but i knew our mates were watching and i was shy so nothing happened. We met out again after that and were flirting and stuff and he'd been texting me, then last thursday we were goin out to the same place and i kinda hoped that something would happen and he was saying he couldnt wait to see me etc but wen i got there he barely spoke to me and ended up gettin off with some girl rite in front of my eyes, i was gutted and ended up goin home in tears cus i rele thought he liked me and i know it ounds so cliche but i thought he was different yet he did that to me wen he knew how i felt about him, i feel so hurt and i dont know why he done this, ive spoke to my friends about it and they are confused too and tell me i deserve better but i still cant stop thinking about him and its driving me crazy inside he's stopped texting and talking on msn since all this happened :s im startin uni next week and i cant even look forward to it properly cause this thing is really getting me down I guess i jus want to know why he hurt me like this and what, if anything, i should do?