i had first day of my period on 9th october 2012 and on 20 october 2012, i had unprotected sex with my boyfriend. on 21october, i have taken i pill as a precaution though my boyfriend was sure that he has not ejaculated inside me but he is not sure about pre-cum. today is 26 and i have received no vaginal bleeding, headache etc after taking ipill. what are my chances of pregnancy?please help!!!!!