I have been getting my menstrual cycle every 11 days i have no idea why?

Not Normal: It is common for young women to have irregular menstrual cycles: have their periods last longer, come late or miss them all together. However, a period every 11 days is not normal. It can lead to anemia (low blood count) and should be evaluated by a clinician if asap if this has been persistent. Your workup will depend on your age, other history, and findings on initial physical exam.