I took an emergency contraceptive and got my period 10 days early. The period only lasted for 3-4 days, when normally it is for 5 days. The period still hasn t come for this month and it is now 12 days late but I m getting mild stomach and leg pain, like how i get before my periods.. What could be the reason for this?. I m only 19 years old.. and i have had irregular periods before.