I had unprotected sex on December 8th, 2011. that was the last time i've have had sex. I had my period starting the Wednesday before Christmas and it lasted the full 7 days. The last few days I've been having bad stomach pains and feeling very nauseous and today I started my period 2 weeks early. I've had a few pregnancy scares before and have taken 5 pregnancy tests, all coming back negative. Since the last time I had sex I only took one test but it was negative and it was the day before I started my period the last time. Is there any chance I'm pregnant or is there something else I should be concerned about?