I'm depressed by default, having a clinical depression, so I've never suffered diabetic burn out like you currently are, by the sound of it... But I have on a few occasions tried to end it (unsuccesfully, obviously), and have dark thoughts creep up regularly. And then I do mean at least once a day. Thing is.... Try to see good things. Not big ones, small ones. Gotta start somewhere. For me it can be running into a cat I don't know who'll let me pet him, for instance. And when I'm out and about with my camera, I'm more aware of my surroundings, so I do notice more. Like a pizza baker with a bunch of geese in front of his shop, who know where to go, because he feeds them every day. When you see the kindness of others, it makes the world a little less dark. See what you can do to make the world a little better, (or more specifically, YOUR world) so you can actually see you being around does make a difference. This place is better with you in it, if you'll just open your eyes to it.
Being a diabetic is hard. I don't know what type you are, I'm a T2 myself, but it's a rough deal whatever way you turn it. (Not saying 1 and 2 are equals, they're just... Hard, each in their own way.). It helps if you don't have to deal with it alone though. This place has a lot of people who've been exactly where you are. They hear you, take you seriously, and may have some advice that's better than mine.
Also... Depression is a condition. Just like diabetes. There's treatment for it. I sadly have to make do without antidepressants due to the side effects, but while it lasted, amitriptyline was absolutely fab, the only one that ever pushed the clouds away and let in some sunshine. I'd still be on the stuff if I could be. There's no shame in asking for a little help when you're down, you know.
Take it from someone who's used to dwelling in the dark.... There's light out there, and it is worth it to stick around.
*HUGS*
Jo