I went online to an ovulation calendar. The first day of my last menstrual cycle (August) was the 28th. Online it said I was most fertile the 9th, 10th, and 11th (being my highest) of September. My boyfriend and I had unprotected sex twice on the 11th, and once on the 12th. It is now September 28th, and what I think was my period started on the 23rd, however, it was way lighter than usual, and lasted four days. And a lot of that wasn't really "bleeding," it was just brown and bright pink. I took a pregnancy test on the 23rd and it came out negative, but it was one that cost like a dollar at the Dollar Store, so maybe that affected the results. Is it possible that I may be pregnant? Can women get their period while their pregnant?