Hello dear, Thank you for writing to HCM. Even though emergency pills are considered very safe and effective, occasionally patients report adverse effects. The most common side effects include: heavy menstrual bleeding, irregular menstrual intervals (periods may come earlier or later than one would expect), abdominal pain, nausea, vomiting, dizziness etc. The symptoms you mentioned are indicative of the side effects from the pill, more than symptoms of a pregnancy (it is very unusual to develop nausea from pregnancy only few days after unprotected sexual intercourse). Even though emergency contraception is very effective in preventing a pregnancy, it is widely advised to take e pregnancy test in order to confirm the result after 2 weeks, for all patients. So I would suggest to take a simple pregnancy test in order to be sure and to avoid using another emergency contraception pill within the same menstrual cycle. Don t forget that emergency contraception is designed for sporadic use, so might need to consult a specialist about a stable contraception method that suits you best. I hope this helped. Don t hesitate to contact me if you have further question. All the best. Dr. Alma