Urinary blockages are urgent care situations: http://www.animalemergencyservices.com/Feline_Conditions.aspx
-- In an advanced, severe case the cat will not be passing any urine at all. You may notice kitty is 'swollen' and feels hard in the abdomen area.
The gums, whites of the eyes and inside of the ears may look yellowish.
You have probably less than two hours to get to an emergency clinic when a cat is this far along.
-- Urinary infections before turning into total blockages can produce symptoms of a cat making odd noises and pacing throughout the house.
They go to the litter box and may make straining noises, passing just a dot of urine or a reduced stream. In some cases there will be blood visible.
Again, the abdomen area may be bigger and feel firm - your cat might show signs of pain when touched there.
--- Most important to realize is that not all cats will show all symptoms all the time. If you even "think" your cat is having difficulty with urine or stools, trust your instincts!
This is a life that's depending on you to get help no matter what day, night, time or expense. Just like a child depends on their parents, your beautiful cat needs you.
AFTER you get treatment, let's try to avoid ever having the problem again:
Many kibble (hard food) offerings from respected suppliers (such as Science Diet, Iams, Purina and many, many more) have specialized diets for urinary tract health, but repeated science suggests feeding predominantly canned/soft food (avoiding a diet of strictly fish or seafood types) may help prevent FLUTD. It’s believed that the increased urine volume dilutes toxic metabolites.
A surprising fact is that many vets aren’t as experienced in feline nutrition as they might be. Some of them are selling or recommending foods based on product manufacturers’ pitches, commissions and free samples.
There is a veterinarian who specializes in feline nutrition and care, providing no gimmick, no ulterior motive information about what cats need for ideal health, even offering homemade recipes and comparing the various foods available without having to spend more than one should. www.catinfo.org
-- I hope things work out well for both you and your companion