Taking the emergency contraceptive pills Levonelle or ellaOne can cause some side effects like headaches, tummy pain, and feeling or being sick. It's possible that it may also affect your next period, making it earlier, later, or more painful than usual.
If you happen to be sick (vomit) within 2 hours of taking Levonelle or 3 hours of taking ellaOne, it's a good idea to visit your GP, pharmacist, or genitourinary medicine (GUM) clinic. They can provide guidance and help, whether it means taking another dose or having an IUD fitted.