please do not be worried. you have done a right thing by taking i-pill within 72 hours of last sexual intercourse. you were not likely to menstruate on your actual due date simply because it takes about 5-7 days for bleeding to occur after taking i-pill. it is also a known side effect of i-pill that the following menses may be delayed or may be heavy. in case periods do not resume in the next 10 days then you must do a urine pregnancy test to rule out pregnancy. if the test comes as negative then please do not take any medication. just wait for your periods to return till then practise barrier contraception. if the test is positive which is unlikely though keeping in mind that i-pill does not cause any congenital abnormalities in fetus you would need to make an informed decision as to continue or terminate the pregnancy (which can be done by medical methods in early first trimester after ultrasound scan confirmation). things can be tackled at each step. so please do not panic stress per se can delay your menses further. try to keep yourself relaxed. consult a gynaecologist online for further follow up --> <link>
i had unprotected sex. what are my chances of getting pregnant?