I'm not sure what pills you're on, but I've done the "continuous birth control" thing (to stop one's periods). You take all three weeks of the regular pills, then, when you would normally take the placebos (the sugar pills), start a new pack. Don't wait a week. Take them every day as normal, so you're taking Week 1's pills, Week 2's pills, Week 3's pills, and right away, a new pack, starting with Week 1. Don't skip any days. The placebos aren't used.