LATE PERIOD AFTER PLAN B

Hey ladies! Well I have a problem, I had sex with my boyfriend and me being very paranoid I had him buy me a plan b pill because we had sex while i was on my period with no condom (after he already came) now its around the time i should be getting my period and I am on day 9 of being late. After I took the pill I had light spotting but still havent gotten the period. Should I be scared? Has anyone else experienced this?