Very frankly speaking,you can not be pregnant because 1st you had unprotected sex during your periods,which is the safest period and 2nd you took unwanted 72 within an hour.Relax as pregnancy
can not take place.
As far as delay in your periods is concerned,it can be possible because of various reasons and the most important is STRESS
take good sleep,drink plenty of water and eat healthy and wait for a week.
If you don't get it,you can consult a doctor who can prescribe you progesterones,which can induce periods in you.