My boyfriend and I had unprotected sex about two weeks before I am to expect my period and he released inside of me. A day or two after that I started experiencing cramping and a few days later my breasts a little sore. I get period symptoms two weeks before my period normally and when we had sex I guess I already started experiencing these. My periods don't come every 28 days as the days are a little off each month. What are the chances that I could be pregnant?