I placed nuvaring on mon 7/28 had unprotected sex on fri aug,1st. ovulation calculator says 8/1-8/6. took plan b on sun 8/3. could i get pregnant stil?

Pregnancy: Nuvaring is not guaranteed to be effective until 7 days after placement. Plan B is about 75-83% effective if used properly. Sex was during a time of higher pregnancy likelihood. So yes, in the above scenario it is possible to be pregnant, though unlikely. If the next period is missed, a pregnancy test should be taken to obtain status.