Hello dear Understand your concern. Postinor-2 is an emergency contraceptive. It is used to prevent pregnancy when taken within 72 hours of unprotected intercourse. It will prevent 95% of expected pregnancies if taken within the first 72 hours. So I think chance of pregnancy is less than 5 % Take one tablet as soon as possible after unprotected intercourse. The sooner that you take the tablet, the more effective. The first tablet should be taken no later than 72 hours after intercourse. Take the second tablet exactly 12 hours after the first tablet. Following are the side effects of pill. It will remain for for 4-7days Nausea or vomiting Dizziness Fatigue Headache Breast tenderness Bleeding between periods or heavier menstrual bleeding Irregular/delayed period due to hormonal imbalance Lower abdominal pain or cramps: as you have also side effects So I think it is be side effect of pills. Just take tablet meftal spas 2 times per day. Drink more water Take rest Take healthy diet Maintain hygiene before and after sex. Drink plenty of water Chance of conceive is very less You can check by Urinary HCG kit /Blood HCG methods if period will be more delayed. If positive still you can use progout abortion kit up to 3 months of pregnancy after consult with gynecologist. Hope this may help you. Best regards Dr. Sagar