Hello, Since you had unprotected intercourse exactly after your previous cycle, it is well that you may have been in the safe period and as such, there is less reason for worry. Stress leads to delayed periods. Firstly, check for the possibility of pregnancy with a fresh early morning sample of urine and if that gets positive see your doctor for confirmation of intrauterine pregnancy and under the doctor s guidance take the abortion pills as prescribed. If the pregnancy test is negative, you can wait for a couple of days before repeating your test; alternatively you can go for the serum beta-hCG measurement and a trans-vaginal sonogram for confirmation. Take care.