i missed my period and I don't know why?

Hi Anon,

Thank you for question and welcome to EmpowHer. A period can be delayed or missed for many reasons. Many teens have irregular periods for many years and it later regulates itself. If you have had a regular period for years then reasons for a missed/late period include:

Stress
Illness
Pregnancy (this doesn't apply to you)
Perimenopause
Being Overweight
Being Underweight
Miscalculation of dates
Change in schedules-- Ie: If you worked during the day and changed to nights
Medications

Usually, a missed period will resume the following month. It may be heavier and longer than the last one you had but this isn't usually something to be concerned with unless it is missed for three months in a row, in which case you will have to see your doctor.

Wishing you the best,

Rosa