I am going through my ovulation period but i had sex on 9th and also used postinor 2. then i had sex again on the 11th and noticed a little blood spot?

Hmmm....: Plan B, Postinor 2, and other brands of emergency contraceptive pills can alter the menstrual cycle vaginal bleeding 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.