I'm so confused...could I be pregnant??

Kimberly
I've been TTC for 3 months and 3 weeks. Right now I'm 17 DPO. Usually before AF, I get cramping. I was due Monday, June 20 but had no prior cramping. I started between spotting and light bleeding on the day AF was due (15 DPO) but I only wore a pantiliner and it wasn't much. By mid afternoon there was nothing. The next day just a little spotting and that was it. I still have had no cramping. I've been doing HPT daily and getting all BFN's. Was that a one day period (mine have been lasting 4 days) or possible implantation bleeding? Could I still get a BFP at all?