That happens sometimes. An important thing to bear in mind is that people aren't entirely coherent by nature, so they are prone to hurting you. But one thing i can assure you: If your goal is to make friends and improve your social life, you're not going to accomplish that objective by mourning your occasional failures. And you should not misconstrue this advice as some kind of personal attack, i'm only attempting to comfort you with what I consider to be a maxim with which to live. If you believe that you don't have enough friends, as you seem to have insinuated, you will gain nothing from regretting the loss of a potential friendship, and that will only depress you further -- you cannot change anything from the past.
It doesn't matter weather that particular peson had some thing agains't you or not; their motives are meaningless to your situation now. Don't ruminate on the reasoning behind their actions and don't bother yourself with the "legitimacy" of your feeling in relation to that. Afteral, this whole situation was beyond your control and you can't do anything to salvage it anymore, so the most productive thing you can do is manage your emotions and move on. You're going to find yourself in a myriad of similar circumstances, and you shall think on how you can modify your behavior in order to better deal with them.
This was a learning experience and nothing more. Be glad. Happiness is increased by rationally evaluating the world and modifying your behavior. Holding on to your "lingering mistakes" is useless, thus delusional by definition. The more delusional you are, the less you're able to be happy.
