Some may experience the following side effects:

• Changes in your period, such as a period that is heavier or lighter or a period that is early or late. If your period is more than a week late, you may be pregnant. 
• If you have severe abdominal pain, you may have an ectopic pregnancy, and should get immediate medical attention. 
• When used as directed, Levonorgestrel Tablet, 1.5 mg is safe and effective. Side effects may include changes in your period, nausea, lower stomach (abdominal) pain, tiredness, headache, dizziness, and breast tenderness. 
• If you vomit within 2 hours of taking the medication, call a healthcare professional to find out if you should repeat the dose.