Have Cat Questions? Ask a Cat Vet Online.
It sounds like your cat is suffering from a bladder or urinary infection. It could even be crystals in the urine or stones.
I suggest that you see the vet first thing tomorrow for a urine culture so that you can figure out how to proceed.
There is not much that you can do for this at home. Most cats need antibiotics and a special diet to cure it.
Let me know if you still have questions.