Does Plan B Cause Delay In Menstrual Period?

I'm on the pill. However one day I forgot and took it about 7 hours later than I normally do. The next day I had sex. We used a condom but it broke so the next day we got Plan B. I'd say this was 36 hours later. (All this was about 6 days ago). I was supposed to start my period yesterday but still haven't. I'm really worried I'm pregnant. Do you think the Plan B my have just messed with my cycle because I took it so close to my period?