well, girls change their minds alot, they also talk behind peoples backs, even if it is her boyfriend. I dont kno about the other guy, cuz to me guys are extremely confusing, they say one thing but they mean the other, or they say something and do the other or the other way around they do something and say something totaly different. so im sorry i cant really help you with the guy thing, cuz i dont even understand guys. hmm... she said that she didnt have a boyfriend the weekend before, and you did nothing about it, so maybe she is getting back at you, trying to make you jelious, to make u want her more?????
i think you should talk to her more, talk to her about the guy shes going out with, talk to her about school, talk to her about everything(girls LOVE to talk!expecailly to guys. most of the girls i know including me are more comfortable talking to guys) and after you get to know her better and she gets to know you better, ask her if she thinks there could ever be anything more between you too, ever. it doesnt have to mean at that very moment, although that would be nice, but just anytime soon.
i hope i helped. and i hope it all goes great.
