If your period is 11 days early, it is most likely due to a lack of luteal function, which is often affected by environmental changes or emotional changes. If it occurs once in a while, do not be nervous, know the volume and color of your menstruation, and if there is no abnormality, observe the next menstrual cycle. This can also be caused by taking certain medications, such as emergency contraceptives or short-acting contraceptives, which can cause early menstruation; submucosal fibroids, large interstitial fibroids, endometrial lesions, and pelvic tumors can also cause early menstruation. Therefore, if necessary, go to the hospital for appropriate examination to find out whether there are any abnormalities in the uterine adnexa and cervix, and then give treatment.