Question for MEDI LINK CONSULTANT CLINICS

Hello doctor. i need to ask a question from you. i and my husband had unprotected sex on 11th may night. he didnt ejaculate inside. after 3 hours i started to bleed. i ignored and considered it as normal. in the morning i found i am having periods. the flow was good and everything was as normal too. yesterday was my second day. the flow of my periods however reduced to half and by night it almost ended. i am confused as what to do. should I take ECP as 72 hours have not passed. i am scared of taking ECP as i have read on internet that ECP disturbs your periods and you might not have periods. i am scared and dont know whether i should take it or not.