I have a regular 38 day cycle. My last period started on the 29th of September, so I was expecting my period to come around the 5th. I had unprotected sex once on the 14th, and that was it. What I believe to be my period started on the 29th of October, first it was just light pink but then it became darker (red) with small dark clots in it, just heavy enough to warrant a liner. This lasted 4 days before it stopped. If this was my period, it would be a week before my period -should- have come. I have been trying to tell myself that our unprotected sex was too far away from ovulation to have gotten me pregnant, but I have been having a lot of symptoms that do not normally accompany my period. Could that have been implanation bleeding, or did my period just decide to come a week early?