Hey, we've all done that once or twice. Doesn't make you a slut, ignore those other people. But let me ask you this, have you ever had sex with a guy and then sat by the phone wishing he would call, thinking that it wasn't just a random fuck, why doesn't he like me, etc? Almost every girl on the planet has experienced that, and if you haven't I'm sure you will. So you know how this guy feels. Nothing really you can do about it now, but in future if you just want a random lay and you're not really interested in a person--try to gauge his feelings first. If he seems obssessed with you, its probably not a good idea. There is certainly no shortage of guys looking for a no-strings-attached fuck that will be *overjoyed* that you don't want to talk to them in the morning. Choose one of those guys when you're in such a mood.
anyway, he'll get over it. that or kill himself. either way, it's not to worry about now
Guys do it all the time, and feel ZERO guilt for it, so why shouldn't girls give them a taste of their own medicine?
Don't beat yourself up over it... if the situation were reversed, he sure as hell wouldn't.