Periods off?

I’ve been taking the pill regularly everyday I’ve only maybe delayed about 20 mins but not more than that and last month my period started a week before i was suppose to be on my period week and then i went on to this month me and my boyfriend ended up having unprotected sex and i took the plan B bc i wasn’t sure what to do and now this month my period was suppose to come earlier in the week but it still hasn’t came should i be worried?