Hello dear I understand your concern You are completely safe, do not worry because 1. You had sex at the 6th day of cycle and it is completely safe period of the cycle. No ovulation occurs at this time no further fertilization 2. You took I pill with in hour of sex and it is highly effective in preventing pregnancy. It has just 0-5% failure rate. No need to take another I pill. I pill can cause earlier period, delayed period by 1-2 week and heavy bleeding can occur So do not worry of period will delay by 1-2 week. Meanwhile avoid stress, take healthy diet, drink plenty of water and do regular exercise Hope this may help you Contact further if follow up needed Best regards Dr. Sagar