Implantation bleeding or period?

Dana

So AF is due March 6th. I started spotting light brown discharge on 2/27 (7dpo) it’s been 3 days and it’s been the same light brown spotting no more and no less. Implantation bleeding or start of my period? I tested today (9dpo) and it was neg. other than sore boobs and fatigue, I don’t have any other mensural/pregnancy symptoms. Thanks for your input in advance!