Hello,
Since you have taken unwanted 72, within 72 hours of unprotected sex, risk of pregnancy is very low. Some women may experience delayed periods in their next cycle after taking this 
emergency contraceptive pill. Other side effects of unwanted 72 are headache, tenderness on the breast, fatigue, 
dizziness, slight spotting or bleeding before the start of the next 
menstruation cycle.
Some also experience body aches, 
irregular periods, abdominal cramps, bloating, and 
stomach upset. Unwanted 72 is a one time to be used emergency contraceptive pill. If you do not want a baby, you should you should be on regular contraceptive pills or device.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Nupur K., General & Family Physician