And welcome to you, Megan and Teddy! We're sorry that you had to come find us, but we're delighted that you did!
You've already taken the most important step in keeping Teddy healthy, by seeking out more information so you can make the best decisions for him. And other folks have mentioned the other two most important things you can do for him: home-testing and changing to a low-carb food, so I'll leave that alone.
May I ask how Teddy was diagnosed? Was he acting differently, or did something happen and he ended up at the vet's? Does he have any other health issues that you know of (even minor stuff like tartar on the teeth can increase blood sugar levels). And I know that Teddy was just diagnosed today, but what has the vet suggested that you do? Have you discussed what type of insulin you'll be giving, how much and how often? And have they talked with you about testing for ketones? I'm not trying to be nosy, just trying to figure out which bits of information to point you toward, 'cause it's going to be a moderately steep (though short) learning curve!
This *is* going to seem overwhelming at first, so my advice is: when that happens, step outside for a few minutes, look at the birds / sidewalk / clouds / smog / whatever, and just breathe. When you're feeling better, head back inside, find Teddy and remind him just how very much you love him. My second piece of advice is to ask questions -- ask lots and *lots* of questions, both here and from your vet. The more information you have on how best to treat Teddy, the better decisions you can make on his behalf, so *please* ask questions! And if you can tell us a bit more about Teddy, what symptoms you saw, and what the vet has suggested, we may be able to give you some more specific advice.
Again, welcome! --
Jean and her Gwyn