I Had Unprotected Sex With My Husband For 3 Consecutive

I had unprotected sex with my husband for 3 consecutive days. On the second day after having sex i took the tablet (option 72 1.5 mg) but somehow on the third day we again did it. But neither of the 3 times he ejaculated inside me. Next month i got my period at the right time on 1st november 2016. But on the second month(december) I still didnt get my periods. Am I pregnant? And I want to know what exactly this option 72 actually does. It was not clearly mentioned anywhere. Does it really stop pregnancy for 3 years by taking only 1 pill. I want to know how harmful it is?