My doctor prescribed me 28-day Tri-Previfem birth control tablets. She told me I could start taking them today if I wanted, even though my last cycle was on 8/4. I forgot to ask exactly where in the pack to start, and all it says in the pamphlet is "Day One Starters" and "Sunday Starters." My periods are irregular, but I'm gauging the next will be on 9/1 or so. There's no guarantee I'll be abstaining from intercourse until then, so I'd like to start them now. What should I do? Thanks!