my AF was a 28 day cycle in the first month after i stopped taking the pill but was longer the second month & then longer again in the 3rd (but that was the cycle we were successful). if you've just come off the pill it may take some time for your body to readjust.

were you monitoring anything like CM or doing OPKs? those things might help you work out your cycle if you're not already checking them

i'd say sit tight & wait for AF but if it doesn't show up, you could go & check with your dr if that will help you put your mind at rest.