So I last had my period on the 18th of March and have since done pregnancy tests! All positive results, two were clear blue digital, one normal clear blue and one in my doctors. However yesterday I got what seemed to be my period, right on my due date! I have no cramps are pain, but have been extremely tired over the last week .... bed by 9.30 and still tired waking up the next morning! 

How could I get a period?