I had sex while i was ovulating and my boyfriend cum inside me so the next day i took postinor 2 will i still get pregnant because i was ovulating?

Probably not: 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.