I know how you feel. I had a dog (Lucy) that was diagnosed with diabetes at the age of 9, and she spent 2 days at the vet's getting regulated. I was then taught how to give her the injections and I doted on her. Just make sure your vet tells you howto regulate her and the signs of her blood sugar dropping. I could tell in a second just by looking at Lu if she was going to have a "seizure" so I kept syrup onhand, but after about 6 months of regulating her insulin, I figured out when it was at it's strongest (when the bottle was brand new) and when it was at its weakest (when the bottle had 1/4 liquid left) so I had to adjust the amount of insulin I'd give her by that. I also kept a detailed chart as to when a new bottle was started, the cc's given, etc.
By the way, cats can reverse diabetes--dogs can't for some reason. Lucy lived to the ripe old age of 14, but it wasn't the diabetes that did her in--she developed liver cancer.
Please take care and learn as much as you can.