Roughly 3 weeks ago my boyfriend and I had unprotected sex on the last day of my period (very light spotting) but he didn't orgasm. We then thought better and he used a condom until we both finished. This was on the Saturday, on the Monday to be sure I went and took the plan B pill. About 3 or 4 days after that i got a normalish flow period that only lasted 2 or 3 days when normally it's 4 or 5. The doctor mentioned that if I have a light period then I may be pregnant. I'm also a few days late. Is there a chance that I am pregnant?