First of all, there's nothing "wrong" with you!
Y'know, your subconscious has great ways of telling you something, and there are plenty of reasons why intimacy could be making you feel panicky.
How much do you "like" this guy? Perhaps you're generally not comfortable with kissing him, and your mind and body are collaborating to say "I don't like this." I can only speak through personal experience, and if I found myself kissing someone that I wasn't 100% comfortable kissing, I'd probably feel like that too.
How old are you? Are you worrying that kissing might lead to other things you don't want / aren't ready for?
Whatever the situation, it's very apparent that kissing this guy makes you uncomfortable and you can't relax. Only you can really ask yourself the questions that will lead to the answer, though...
[This message has been edited by earth girl (edited 05-05-2002).]