Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
My thoughts and suggestions are as below. Since you have already taken Sulfameth/TMP for UTI, your symptoms should have been settled. You still have constant urination with little urine indicate that there may be continuation of
urinary tract infection or also have associated problems like
enlarged prostate,
prostatitis, or some obstruction or so.
Hence I would advise you the following:
Continue taking more fluids.
Take urinary alkalizer with a glass water after food.
Send the blood for tests of CBC, kidney function, diabetes.
Urine for: Routine, microscopy, culture and sensitivity.
Ultrasonography of abdomen, particularly for genitourinary system.
Consult your Doctor asap and get an appointment of a
Urologist.
You can continue with an antibiotic as before if the course of 14 days is not over.
Hope I have answered your query.
Let me know if I can assist you further.