In my opinion, investigations like kidney functions, blood sugar levels, ultrasound lower abdomen ,intravenous pyelography , pregnancy blood test,
thyroid function tests
and cystoscopy may be needed to confirm a diagnosis. I sincerely advise you to consult a urologist or nephrologist and get yourself evaluated so that a confirmatory diagnosis can be made. But firstly try drinking plenty of water because if it is simple UTI, then adequate amount of fluids will flush out the infection.