HELP

I had sex January 13th 2013, it was unprotected, i took next choice 2 days later, and i got my period 3 days after i was supposed to. I recently had protected sex on January 26 , the day after my period ended, i took no morning after pill , the only contraceptive we had was a condom, it didn't break or anything, he pre-ejaculated, but he said it was in the condom, nothing got inside me. This week my stomach has been upset, it's been growling and gurgling, I've felt little gas bubbles inside me, they pop. I also feel a tingly feeling inside my stomach , and a pulse? Sometimes my stomach feels like it's kind of burning? & I'll get the feeling that I'm hungry when I'm not? I also feel like throwing up randomly, in the morning, after I eat and what not, but I don't throw up. What could this be ?! From my calculations, my fertile days are Jan. 30, I ovulate on Feb 4th, and my last fertile day is Feb 5th. HELP !!!