Thanks for contacting HCM with your health concern 1. Since both regesterone and i-pill are oral contraceptive pills with high hormonal content which means that there will be slight withdrawal bleeding in coming weeks and your routine periods will get delayed by 8 days. 2. i-pill is an emergency contraceptive while regesterone is for regular use and since presently there will be hormonal imbalance I would suggest not to take one after the other or continue as regular contraceptive, instead, wait for your regular periods to come [in mean time use barrier contraceptives like condom] and thereafter consult a gynecologist as how to continue the pills every month [till you want to avoid pregancy], which will give you an ideal contraceptive effect and help from getting pregnant as well will keep your periods regular PS. also anxiety/stress usually can cause delayed periods