Sharp pains when having sex?...?

[MissJayyy]

I recently just started sleeping with a new guy I'm dating, but it suckkkkkkks because every time he goes too far in I get this awful really deep achy sharp pain on either side and it HURTS so bad it takes my breath away and just kind of kills it for me. I've never had this prob. before with any other guy I've been with however he is much bigger than any of them, which probably has something to do with it.. but like, what could be causing that? It's terrible and need it to stop, asap :/