I had sex with my S.O. on the 10th of this month. We didn't have a condom handy, because it was spur of the moment. He withdrew before he came, but we went for a second round and he didn't clean himself up before we started again. We both gave up after a little while because we were both just too tired. I just started my period, but I've been told that you can have your period and still be pregnant. So is there any possibility that I might be pregnant?!?