The first day of my last period was sometime around April 13th. On April 29th I had unprotected sex (not very smart) and 3 or 4 days later I had a very short "period" but it really wasn't a period I believe. It did not seem right like a possible implantation bleeding. That was around the first week in may. It is now June 12th and I still have not had a period and a home pregnancy test was negative. Could I be pregnant or could it be something else?