Yesterday on 15th Feb, we had unprotected sex. Though he used Pull Out (Withdrawal) method, I thought that there may be a chance of pre-ejaculation. So as a precaution of unwanted pregnancy, I took an "Unwanted 72" pill after 25 hours. My period cycle is coming on 18th. I just wanted to know that, when will I get the withdrawal bleed? If I don't bleed within a particular time period, does it mean that his sperm didn't enter my vagina? I thought that withdrawal bleeding happens only if his sperms enter her vagina.