How many days after starting you pack of birth control pills does it take for your period to end?

I should know but surprisingly I have never paid attention.. I started my period Saturday, just like I always do.. and I take my first pill on my new pack on Sunday (today).. I just realized that my anual pap is Wednesday.. I think I will be finished by then but not real sure.. I already asked off for work and I would hate to have to reschedule because my boss doesn't like for me to miss alot... Will they still do my pap if its still light (days were I have brownish discharge)? Do you think it will have ended by then?