I had unprotected sex a couples days ago. but i took an emergency contraceptive pill the day after now i am wondering when i will have my next period.

Unpredictable: Emergency Contraception is only about 50% effective at preventing pregnancy. Waiting a whole day before taking it makes it even more unlikely to be effective. But, there is no predictable way to tell you when your next period will happen. You may be pregnant. Emergency contraception, when it works, will change or interfere with menstrual cycles for up to two months.