Okay! So I had unprotected sex on December 21 2012. I started my period on the 22nd and it went on til the morning of the 26th (normal period for me). I then had sex again that night. I was expecting a period this month around the 21st 22nd etc... Instead I began spotting on the 14th. Exactly a week before my "supposed to be" start date. The spotting was light brown and only showed up when I wiped. Lasted only 4 days. I've taken 2 tests since then and even had blood work done... Not pregnant. Does anyone have any clue what might cause this? It's a first for me.