I'd be concerned if he's not feeling well, not eating well and not getting insulin. That can be a recipe for ketone development. Are you testing his urine for ketones with human strips from the pharmacy? I strongly recommend you start today. If he's no better by this afternoon I'd call the vet for advice. There's little margin for error with a diabetic kitty.
Re insulin: he
needs it so I'd try a small dose of 0.5 u. If he eats even a teaspoon or two of food by insulin onset (+2 to +3) he should be OK.
In case you haven't seen this:
Here are some tips on how to do urine ketone testing (VERY important if BG is high and kitty isn't eating well!):
- put the end of the test strip right in his urine stream as he's peeing
- slip a shallow, long handled spoon under his backside to catch a little pee - you don't need much
- put a double layer of plastic wrap over his favourite part of the litter box and poke some depressions in it too catch pee.
Most test strips have to be dipped and allowed to develop for 15 seconds before viewing the colour change in very good light.