Implantation, spotting, or just a really stupid period?

I tested at 10, 11, and 12 DPO - all BFN. I had light cramping during that time, but nowhere near what I would have before a regular period. I started bleeding the day I was supposed to get my period (14 DPO), but it was lighter than usual. It seemed too heavy to be spotting. The next day it got lighter and the past 2 days it has just been spotting, almost non existent. I usually have very heavy periods in the beginning and cramps through the 3rd day. They are also very consistent from month to month.I tested yesterday and this morning - BFN. Any ideas on what the heck is going on??? Do I still have a chance at BFP? It's killing me having such a weird cycle this month and only BFN...