If you read the above post, it explains the side effects of the pill, which is probably what you're experiencing.
I had unprotected sex on 12th of Jan 2016 and took postinor 2 on Wednesday, I started bleeding on Sunday 17th for 3days. but Im now having bigger breast with pains and also the feelings of vomiting. Pls someone should tell me the problem.
Thank you for the reply. Yes, I am considering birth control pills soon. It's just worrying me that these apparent side effects are actually side effects and not indication of pregnancy :( Especially when I can't do a pregnancy test yet because most sites recommend testing after 3 weeks' time.
A message from the manufacturer:
"Side effects of Postinor-2 can include some nausea that may lead to vomiting, although most women experience only a short period of nausea after the first dose. Fatigue, dizziness, and tender breasts may also result from taking Postinor-2. Generally, these effects will be mild and will fade within a few days. In a very few women, the next period may be unusual. Any changes in menstrual bleeding, or increases in pain from the normal period should be reported to a doctor immediately."
Also, it's not advisable to regularly take the morning after pill or emergency contraception pill after every encounter of unprotected sex as it can have various long-term effects on your cycle and reproductive ability. If you're taking Postinor-2 every week, or even every month, then see your physician and go on birth control and use condoms as a method of contraception. If your taking Postinor-2 up to five times year in separate cycles, this is considered safe. Anything more, get birth control or use condoms.