Re: Cheese & BG levels
Cheese is fairly low in carbs but it has some (it's made from milk which contains sugar), and it also contains a reasonable amount of protein. Many people find that if they eat a low-carb meal, their body converts some of the protein to carbs. Personally I divide the protein content of something by 2 to get the amount of carbs my body extracts from it.
That's the most likely cause but with diabetes, a lot of weird things can happen.