Hi. On april 6th i took morning after pill after i had unprotected sex on the 4th. My period came on time 14 days later and was very light and lasted 3 days. Yesterday, may 2015 my period 4 may came nd it lasted 4 just a day. Ave been having terrible abdominal and back pains. Blood tests for pregnancy are negative. Nd ultrasound isnt showing anything. Please help. What could be wrong? Could it be ectopic? I wud be 8weeks 2moro.