If you happened to be taking the pill on a daily basis without any failure, there was actually no need of additional protection since you had a protected cycle. This additional dosage may lead to hormone disturbance and hence can delay your next period. Yet, since you had only one additional pill there may not be much delay in the onset of menstruation
and hence, you should take the help of a specialist if you become overdue by a week. Further management can be planned after a pregnancy
test and a sonogram . Hope this helps.