Thanks for trusting me to help you and Spot today. I am a licensed veterinarian with over 30 years of experience and would be happy work with you.
Based on her behavior, it is not safe to assume that she has a urinary treact infection. Your very first step should be to have her examined and to have a urinalysis performed to verify if there are any microscopic abnormalities. Blood, if present, can be a sign of inflammation (not always due to bacterial infection) and can be microscopic. The causes are varied and the age of the cat partly influences the likelihood of the cause. (ie older cats are more prone to bacterial infections than younger cats). Other common causes include bladder stones, crystals, tumors, and sometimes just inflammation from an unknown cause (more common in younger cats). This latter condition is called feline idiopathic cystitis (FIC) and is often precipitated by stress. Unfortunately, they all can show the same symptoms, no matter the cause and all are treated a little differently. If her urine is completely normal, it may be a behavioral problem, which is often precipitated by stress as well.
If it is a bacterial infection, she needs antibiotics. If it is a stone, it needs to be removed. It is possible (and likely) that there are no bacteria at all and it is a problem is due to FIC. The good news is that many of these cats with FIC will improve on their own regardless of what treatment we provide. Usually we try to give them something for their discomfort. It is not uncommon for their symptoms to return again later and can come and go periodically throughout their life. Unfortunately, there is not a test to prove FIC is the cause, and this condition is confirmed when all other causes have been rule out. That is why a urine culture is essential as well as some sort of imaging (xrays or ultrasound) to rule out stones, tumors, etc. (Some types of stones will not show on a plain xray). I would urge you to make sure your vet cultures her urine and doesn't just put her on antibiotics and assume that because she gets better, there was an infection. If she has FIC, it is important to note it as it is often a very recurrent disorder.
In the meantime, I would try to encourage increased water intake as best you can by adding water to her food (as much as she will allow) or providing a pet fountain.
I hope this is helpful. Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please reply so I can clarify for you.
My posted replies are for general education only and not meant as a diagnosis. Only after a thorough veterinary examination can a diagnosis for your pet be made and specific treatments be advised or medications be prescribed.