Crikey - Diabetic AND Vegetarian. :shock:
I'd suggest NOT being a vegetarian (although I doubt you'll want to do that!)
Bread, pasta, potatoes and other root vegetables, pastry, flour - all these things will have a negative effect on your BG. You'll need to find out HOW eacjh of them effect your BG, or, you could just stop eating 'em!
Do you eat fish? Oily fish is great for diabetes, and shellfish are a good option for keeping BG down.
Good news is, stuff like cheese and nuts are still on the menu. Stuffed peppers, stuffed mushrooms, etc.. All good stuff.