When to start birth control pills?

i just got a pack of ortho-tri cyclen pills and i need to know when to start the pack... today is monday and i started my period on friday, so the correct day would have been yesterday.. so should i leave on pill and take the one for monday or should i take the one for sunday and just be one day behind?When to start birth control pills?
Technically you're supposed to start the first day of your period. However, you can also start the Sunday after your period starts even if you're still having it. I think it may be too late right now to start, but talk to your doctor and see what he says. You might have to wait until your next period. Good luck!!!
there are two days you can start your pills: the sunday after your period or the first day of it. since it is too late for you to take it on the first day, take it the sunday after your period is over. you won't be protected from pregnancy for at LEAST a week (some say 2 weeks or up to a month), so use protection in the meantime.