Hi, Thanks for the query. Your doctor has given you progesterone tablets for withdrawal bleeding. This can temporarily help but to prevent future recurrences and to regularize the future cycles better to get evaluated. At the time of menarche some amount of abnormality can be there during periods. But usually with passage of time the periods should regularize. Irregularity in periods can occur due to poly cystic ovary disease, thyroid abnormalities, stress and strain etc. So by undergoing physical examination and ultrasound the cause can be found out and treatment can be given according;y. Take care.