It’s very common to have irregular periods during the first couple of years after you start menstruating. You might also be one of those young women whose periods are affected by changes in body weight or diet, increased stress, eating disorder, exercise, illness or going away to camp or college. Your period may last 1 day or it may last 7 or 8. All of your cycles may not be the same number of days, and the length of your cycle may change over time.
If your periods are less than 21 days apart, your period is heavier than usual or your periods are irregular for 2-3 months, make an appointment with your primary care provider (PCP). Also, if you are sexually active and your periods are irregular, make an appointment with your PCP. Keep track of your periods using a calendar- when they start and stop, and the amount of flow you have. Bring your calendar with you when you see your health care provider so he/she can evaluate your cycles.