Hoo boy can I relate! About the snapping, anyway. Unfortunately with me, it happens after I've known the person for a while and just can't handle them any more.
Lovie, there are DEFINITELY ways to get help; talking to a therapist if you can afford it is usually a very good option because it will help you PINPOINT exactly what about meeting others sets you off so you can compensate for that. There are also mood stabilizing medications you may want to ask a psychiatrist about; I've used them before and they do help me keep calm (I think they'd be good for your situation because it seems like you lose control if even slightly provoked, so the medication could prevent angry outbursts). The best thing to do would be to talk to a professional, of course. It's really good that you already recognize behavior you want to change