Yeah, I second that. She could be scared and confused, and just act cool to hide it all. Or was she trying to make another guy jealous? What were the circumstances when she kissed you? (Was it just the two of you alone, or in the middle of the dancefloor/everyone else around...? Were you guys drunk, or just one of you? And what do you mean by 'if you could call that a kiss'?)
Some people just kiss on the dancefloor and mean nothing by it. Especially if they're too drunk. Or she could be really in love with someone else. Or with you, and seeing if you'll make the next step now.
How did you approach her last night? Did you go up to her and talk to her, or just waved from afar, expecting she'd come to you? And if you did go to her, did you expect her to do all the talking etc? (She was maybe waiting for you to impress her. Ha.) Did you ask her to dance with you or pull her to the dancefloor? (If she likes to dance.) Did she see you dancing or talking/laughing with another girl - she might be jealous?
Maybe you could walk up to her in person next time you see her and say something funny like, 'Now that you snogged me you don't want to talk to me no more? I feel used.' But only if you can pull it off in a funny way. (Think how mrb would do it-??) You could even ask her, 'Was it that bad?' (Maybe it was, lol) 'Don't worry, I still respect you.' Or something like that. And see what happens?
Some PUA tips might be helpful for you too, hmm.. (But please don't take the whole PUA mentality, it can be horrible..)
I've been kissed by a guy who totally ignored it next time we met. And I've been kissed by guys I sort of ignored later too (usually cause I was confused, not sure, or a combination of the above.)
There were even a few guys I ignored cause I thought my friends didn't like'em. (I was young and stupid-??!!) Or I just saw them behaving in a way that I thought I could do better than that or that we weren't really compatible or something, or that they were drunk so they didn't mean it, maybe they weren't really interested and if they were they would make an action to show me... I think that many of them, if they approached me in a right way, might still have a chance..
You could also ask her (girl) friends. They may know more.