Pregnant? Or body back to normal?

I stopped my bc on June 29 and about a week later I got my period which was wierd...it lasted about 12 days and we had unprotected sex a couple of times. I've done 4 pregnancy test and all negative I haven't done one in 2 weeks but today I started to have moderate pain on my right lower stamach and my breast are a little sore ....we had sex on Tuesday but he pulled out....is it possible I can be pregnant? ??? Or is my body just trying to get back to normal ???? And if so how long does it usually take to get it back to normal and get pregnant?