Hello and welcome!
Thank you Nan. She is currently on one unit twice a day of ProZinc. We are not home testing as of yet, we are heading back to the vet today to hopefully get the UTI figured out. Is it normal for cats with diabetes to act differently once they start receiving insulin? I know when I change my diet and medications it takes time for my body to regulate, and her body is so little I'm sure she is trying to regulate as best she can. We are just so concerned because she seems to have gotten much worse since the diet change and insulin. She is so lethargic and tired all the time. This morning she wouldn't even eat breakfast so we haven't given her the insulin yet as the vet advised it not be done on an empty stomach. So happy to have found a community with other people who are dealing with the same thing.
No, not normal. If anything, insulin should be helping to bring blood glucose numbers down, which should decrease the amount of drinking/peeing Reg does. There are two possibilities:
1) Reg has developed a UTI. If the amounts being peed are small, but frequency of trips to the litter box have increased (which is what it sounds like), it's probably this. Call the vet, you'll probably have to bring her in to get checked out and on antibiotics to fix it.
2) Reg's BG numbers may have actually increased after starting insulin, so she's behaving more like an unregulated diabetic cat (extra drinking/peeing). This sounds totally unintuitive, but it does happen; basically, insulin brings numbers down below the level that the cat's body is used to, and there's a compensating reaction from the liver to release extra glucose into the blood to bring numbers back up. I think this is somewhat less likely based on your description, but it's possible.
A few questions for you: what kind of insulin is Reg on? Are you doing any home testing of blood glucose? We're big advocates of that here; we think it's the best way to keep your cat safe and do sensible dosing adjustments (without having to go to the vet for glucose curves or fructosamine tests!). And it can help give you peace of mind and more of a feeling that you are in control of the situation-- this is a pretty overwhelming diagnosis, especially at first!