anyone experience this before???

On the 20th which was 7dpo and had implantation bleeding. Af is due tom and negative pregnancy tests for the past 3 days. I never ever spot in between and it was just when I wiped one time. This would be my 2nd child if I am pregnant. I had implantation bleeding on the first one too. Anyone have af not show up and get a bfp that day it's due or days after and negative before? Just curious.