I took 2 tablets of postinor2 instead of 1.my period started exactly one week later. usually on the 3rd day it gets light. but my flow is still heavy.

Pregnancy unlikely: Plan B, Postinor 2, and other brands of emergency contraceptive pills can alter the menstrual cycle for the cycle in which Plan B or Postinor 2 was taken, and sometimes the next month's cycle too. One should be sure to check a home pregnancy test about 3 weeks after sex, because emergency contraceptive pills work most of the time, but not all the time.