I don't get my periods regularly. Every 2 months or so i get my period. sometimes it's longer. Anyway i had gotten my period around the 20th of july. It lasted about 4 days, about 2 days later my boyfriend an i had unprotected sex. The very next day i got the plan b pill and took it that same day.Today, july 31st, i got my period again. Is there something wrong? could it be a side affect or a possibilty the plan b didn't work?