Size and quantity?

If a guy has a really big penis and cums like really a lot, can I get pregnant easier then with a guy with smaller penis? My bfriend has a really big dick and produces a lot of cum, we've been having sex a lot without a condom and he tells me won't cum inside me but then he does cum inside me, and tells me he can't help it, that I feel to good inside, he can't control himself. I think that I've missed my period, OMG! what do I do? Also if I'm having sex with my bfriend and he's wearing a condom and cums inside it while he's inside of me and it falls off inside me, can I get pregnant also?