Okay so I had unprotected sex on December 31 2013 but we used the pull out method. I got my period on the 2nd of January and then again on the 29th I was supposed to get my next period on the 27th of February but didn't start until the 9th of March. It's very light with some brownish red discharge. Anyone have any idea of what it could be? I did take two cheap pregnancy test that came back negative.