Hello Thanks for your query. I will try my best to provide you with best possible professional recommendations to your questions. These medications are hormonal preparation. I advice you not to take them routinely as they have there own side effects. I advice if you are not planning to be pregnant kindly consider some contraceptive methods. Side effects depend on the content of the pill that you have consumed. Few of the common side effects include nausea, vomiting, abdominal pain, fatigue, headache, dizziness, and breast tenderness. Side effects usually do not occur for more than a few days after treatment. Others like temporary disruption of the menstrual cycle is also commonly experienced. If taken before ovulation withdrawal bleeding a few days after the pills can be seen. I think you might have taken it around your ovulation so bleeding can be seen. I advice you if the bleeding persist more then week kindly see OBG specialist for through examination. Yet again, I do hope that you have found something helpful and I will be glad to answer any further query. Regards