please help!! 

Me and my ex first had sex on Oct 6th, about three months ago, and we continued to do so while using protection. I have had my period every month since then, and have taken two test that have resulted in negatives. Just recently we met up and had unprotected sex, but he pulled out. I've had no signs of pregnancy, any in three months, but I'm still scared. Sometimes I have pains on my right side that move to the left, and sometimes to the middle of my stomach. I've decided to take another one if I don't have my period within' the next two weeks. If anyone could help me out it would be greatly appreciated! Thanks in advance!