Getting a period twice in the same month is not typically normal and can be caused by a number of reasons including anemia. Other reasons why someone would get their period more frequently than normal include stress, extensive exercising and changes to one's lifestyle, according to the Center for Young Women's Health.
Most women have a menstrual cycle of approximately 21 and 35 days, with most periods lasting around 3 to 7 days. Whenever a period is occurring more frequently than once per month, it's important to bring the issue up with a doctor so they can determine the cause. A doctor might want to perform a blood test to check the patient's red blood cell count to check for anemia.