Implantation bleeding or period?

Mary

Hi! I just need some help here! I had my last period the 12 of July and had unprotected sex with my boyfriend the 19. I took plan b the next day, less then 12 hours and had no symptoms at all. Its been 8 days since i had the pills and 9 since i had sex, so im so afraid it may have implantation bleeding. Yesterday i had a medium flow of brownish blood. I’ve never ever had bleeding in the middle of my cycle and im so scare of what’s happening now.