Implantation bleeding?

Dahlia • TTC Baby #1. Baby dust & good vibes!
What does implantation bleeding look like? Or is it different for every woman?
AF was supposed to arrive on the 6th but no sign of her & today I'm seeing very little brown spotting when I go to the restroom. I've taken two pregnancy tests and they both came back negative. Could this be implantation bleeding or AF approaching?