Yes,Bactrim can cause fever.
Thanks for writing to us
Your nurse has given you right suggestion to stop Bactrim.You are allergic to sulpha group of drugs.You are rightly taking Benadryl.
Bactrim contains sulfamethoxazole and trimethoprim
and allergy is due to sulfamethoxazole.
Serious side effects of Bactrim are severe skin rashes,fever,bleeding,aplastic anemia
,jaundice,mouth sores,joint aches,itching,sore throat
Fever may be due to both,UTI or side effects of Bactrim.
After stopping Bactrim you should take another antibiotics like Cephalosporins for UTI.It is ideal to take after culture and sensitivity report.
It can take 3-4 days for full recovery.
For fever you can take tablet paracetamol
500 mg SOS if fever > 100 degree Fahrenheit.You can also do sponging.
In future you should tell your doctor about sulpha drug allergy
Get well soon.
Hope i have answered your query.
Further queries are most welcome.