Why do I feel sad still even though it was just a kiss?

You were probably attratcted to his personality. You have good time with him and enjoy talking to him. It seems to me that you WANT to be in a relationship, but some part of you is holding yourself back. The part that is telling you that he might be a player (you know about first impressions) and that he may not be able to hold a long-term relationship like you want. You want to save your virginity for someone special, but at the same time you want to give it to him because you think that he may be that special someone.