I have been on 2 different antibiotics for uti but i still feel symptoms when i don't drink enough water. could this be something else other than uti ?

Residual symptoms: The symptoms a a UTI can persist for a few weeks after a urinary Tracy infection has resolved. If you are generally better then just wait and see if the symptoms resolve over time. If you are feeling worse then before, see your doctor

Yes: It might just mean that you have not yet used the right antibiotic for that germ or it could be something else in the bladder, urethra, or vagina. It is time for a urinalysis and culture, and an exam if that is normal