Hello Lucy and Lola, and welcome to FDMB!
I think many of us had that 'deer in the headlights' feeling initially. And it's understandable. The diagnosis
does come as a shock. But then we soon find out that diabetes is treatable, and, if we're
very lucky, we come across FDMB!
Your vet may well want to sell you a 'special diet' for diabetic cats, but our experience here is that a special diet is absolutely
not necessary. Diabetic cats do really well on ordinary low carbohydrate canned/wet food.
What is Lola eating at the moment? Wet food? Dry food? The reason I ask is that dry food raises the blood glucose levels. So switching to a wet/canned food would lower the blood glucose levels. This means that if the vet suggests an insulin dosage based on Lola's blood glucose levels while she's on dry food, that dosage might be too much if she switches to wet/canned food. For that reason we recommend only switching to a lower carb food if the cat's blood glucose can be tested at home and the insulin dosage adjusted accordingly.
'Hometesting' (testing a cat's blood glucose at home) probably sounds a bit scary, but it really isn't hard to learn. Honestly. It only involves taking the teensiest weensiest droplet of blood from the outer edge of your cat's ear. This shouldn't hurt her at all. I test Bertie while he's munching on a couple of treats, or while he's dozing in his basket. Most of us here use ordinary glucose meters made for human diabetics.
Some lucky cats go into remission (become diet controlled diabetics) after just a short time on insulin and a switch to a lower carb diet. But even cats that don't go into remission can have normal, happy and healthy lives.
Here is a link to basic 'hometesting' info so you can see what that's about.
http://www.sugarpet.net/bloodtst.html
Eliz