Hi Wendy and welcome to FDMB.
We understand how overwhelmed you may feel right now. We have all been there.
Feline diabetes is something that can easily be managed through proper diet, insulin and hometesting. For diet, we recommend a low carb/high protien canned or raw food diet. No dry food. Dry food is high in carbs and will keep your cat's glucose levels high. It also means you will need more insulin to control it. With the proper diet and insulin to kick start the pancreas, many cats have been able to have their diabetes diet controlled. Hometesting means using a human glucose meter to test your cat's blood glucose (BG) levels before every shot. This is done to first, determine if it is safe to give the insulin dose & second, determine how well the insulin is working and if a dose change may be needed. We can help you learn all of this.
You can help us understand what you need by telling us what your cat is currently eating and if your vet prescribed insulin, what kind and what is the dose.