I'm sorry about your kitty, she sounds sweet. We're totally cat people here.
We lost one about 1.5w ago. He was not himself (not talking, talking, talking), decided to watch him overnight. Emergency vets have always been so costly, and if he was really sick we wouldn't have enough $ anyway. So far it's always been ok the next day to go see the regular vet after spending $$$ the night before. We don't know what happened, might have gotten hit by a car but he didn't have wounds or sore spots.
Put him in my son's room overnight and gave him some cat bup (leftover from the last one who got hit). He jumped out my son's high window, laid down and died in the yard the next morning. He hadn't been gone long when he was found. It hit me harder than I thought. My son coming up to wake me with "Boggo died!" has been re-lived in my mind so many times. Second guessing our decision to save $2,000 on an exam, IV, xrays, and overnight stay which is what it was last time but unnecessary...
My son loves kitties more than life itself. He's a 19yo crazy cat lady.
Some have 9 lives. Some apparently don't. :~{