Pregnant or not ?

Me and my boyfriend had unprotected sex on Monday March 9 and on Thursday March 13 , he says he "dosent know" if he chummed in me but he is super paranoid about me being pregnant in fact so paranoid be bought me emergency contraceptive , I took it on the 15 that morning , could I be pregnant ???? I'm very scared my period usually comes by now I'm just hoping it's the pill that threw it off I've never taken one before ,