2 periods in 1 month, took plan b & now no period

i had 2 periods during the month of october & the last one was on halloween weekend (Oct 29) & according to my period tracker on my ipod, my next period was supposed to be on Nov 16 (but according to my 28 day calculation im supposed to get it on Nov 25) i was not intimate during that time, i was intimate & took plan B on nov 29 just a few hours after unprotected sex, i completely skipped my november period which i thought it would just be a week or so late since my period usually comes a week or two late (or come in early Dec) but it is now Dec 12 & i still have not gotten my period