We had a sweet little girl kitty, a tortie point Himalayan who was 16 years old.
Last year she had the exact same symptoms.
She had renal failure and nothing could be done.
We cried and it broke our hearts, but we had to let her go or else let her suffer. Not to mention the mess in the house.
One month later we lost another kitty to complications of dental disease. That kitty was 17 years old.
2 cats in 1 month? May God comfort you for your loss. And a big (((hug))) of comfort to you and your family.