Could this be a sign of pregnancy? Sorry if TMI!?

had unprotected w/ hubby day of (or maybe it was before) ovulation, except he didn't "finish". It was a Saturday and I went to work and while I was at work he, you know.... took care of business by himself. So a few hours after he did that we had , I finished but he couldn't (for whatever reason). I'm due for AF around the 13th but now I'm having the worst stomach pains and back aches. I guess I'm feeling a little bit nauseous, but that could be all in my head. What do you think? Could I have possibly gotten pregnant even though the deal wasn't sealed? He did masturbate a few hours before and I've read that that could cause sperm leakage...