Could Fasting, Diet, Or Sleep Changes Cause A Delay In Periods After Intercourse?

Hi, i got my last periods on February 28th after that i had intercouse only once on 6th of march and we use pull out method, usually i got periods 4 days earlier from the last periods which means on march 24th. Mostly but not always. I m anxious about pregnancy. I want to avoid pregnancy. It s a month of fasting my diet sleeping pattern everything changed. What maybe the reason for delay in periods. And what should i do to get my periods immediately. I need to wait for few more days or can i use some natural contraceptive methods. Can you please suggest me.