Is There Any Need Of Taking Contraceptive Pills If I Have Irregular Periods And Had Safe Sex ?

Hello! I m 19. My boyfriend and I had intercourse last Saturday, 4th of June. The same night, I had a feeling (that feeling girls get) that I was going to have my period. And for the last 2 months I ve been getting my period on the first week of the month (it also ends before the 10th, 5 days) those are the months of April and May. I skipped the month of March and before that, I used to get my period on the last week of the month. (Is my schedule messed up?) But my bigger concern is, I already had that feeling but I still don t have my period now, 8th of June. Should I be worried? Should I take emergency contraceptives? We used a condom, btw but he didn t pull out. I would really appreciate your help!