The effectiveness of plan b decreases the longer you wait to take it. I don't want to scare you, but I got pregnant with the plan b pill. I took it 14 hours after sex. I experienced bleeding a few days later, but it was enough to make me think I got my period. It was browner than usual but I still thought it was my period. Currently 40 weeks pregnant. If I were you I would wait a week and see how you feel, then take a home pregnancy test. Hope everything works out in your favor
Spotting is a common side-effect of Plan B. You can also expect changes in your regular period for the next couple cycles.