helpp!! I cannot be preggyyy

I had sex on the 10th of March and and started the pill the next morning. I was on my period and we used a condom. but now I'm on the sugar pills and I still haven't started my period. I'm 2 days late. I did a lil research and it said that on the first pack it's typical to be late or not get it at all or sum. but should I be worried ?