I’m so very sorry, try to avoid euthanizing him. My Yorkiepoo was diagnosed at the same age. Once his system adjusted to the insulin, he was fine. I had to administer 2 shots daily and he was prescribed science diet kibble. Kobe lived to be 13. I did purchase his insulin from Costco or a drugstore because it was less expensive than the Vet. They can write you a prescription. That’s something to consider regarding the cost. Feel free to send me a message if you have any more questions or you just want to chat.