Can i still get pregnant if i took plan b tues morning (11 am) and then took bactrim (sulfamethoxazole and trimethoprim) antibiotic thurs.( 7 pm) ?

Possible: The Bactrim (sulfamethoxazole and trimethoprim) doesn't increase the risk of pregnancy after taking Plan B but Plan B is only 95% effective if taken within 24 hours after unprotected intercourse so there is still a risk of pregnancy. Now is a good time to consider starting a more reliable method of contraception along with the use of condoms to decrease the risk of STDs. Hope this helps. Be safe.