Thank you so much for your answers
You can get pregnant at any time while on birth control pills. it does not matter what day it is or if you're on the regular pills or placebo. birth control pills are not 100% and LOTS of women get pregnant while on them even though they take them correctly. if you are having symptoms take a home pregnancy test asap so if you are pregnant, you will know to stop taking the pills.
Depends.
If you've just started them then I would be sure to add condoms to be safe. But if you've been on the pill 3 months or longer and your 21 days of pills have stopped and you are on the white placebos, you'll be ok. (so long as you didn't miss any of the 21 pills)