Pregnant?

I'm not supposed to start my period for about a week or so. My boyfriend and I always have unprotected sex, and the last 3 times, he's pulled out at the VERY LAST MINUTE. I have been having slight side and lower stomach pains. Nothing bad or major, just enough to know it's there, you know? It's too early to take a test so I don't want to waste my money just yet. Any way I could be pregnant? ( I am not on any birth control or anything, and we've never used condoms. )