While taking septra, (sulfamethoxazole and trimethoprim) all im drinking with it is water. Thts all I drinkin. Which im peeing a lot more. Is that normal? . Is the infection flushing out?

Polyuria. More than 3 liters urination/d is polyuria. Frequent urination can be seen from many causes. 1. Increased fluid in means increased fluid out (antidiuretic hormone at work); other common causes are a urinary tract infection, high blood sugar (diabetes) and more worrisome, kidney disease or brain hormone problems can cause excessive urination. You are young & have a uti; would guess it is fluids.