Period started early, but lasting really long. Not sure what's going on.

During the middle of the night I got really sick (coming out both ends). Next day i got my period, which was 3 days early. It was super light and the next 2 days like nothing, just dark brown like it usually is when my period is ending. Thought it was over, but it's still going. Was hoping it was implantation bleeding, as we have been trying to get pregnant for almost 9 months now. But, tomorrow will be day 7. It's still been light. My periods only last 3-4 days and come the exact day they are due for the most part. Ever since I got sick, I've had on and off stomach aches and cramps. Not sure what's going on...