I remember you saying last week that you might try Jenny Ruhl's bagel test, and it looks like you have.

If you have been eating LC for a while, your tolerance for sugar/starch will have diminished. It is recommended you eat >100 grams of carbs at least 3 days before embarking on a glucose tolerance test. I don't know if you factored that in.

Assuming you did the above, and your numbers were that high, then you should be afraid. Afraid enough to keep those numbers in mind when you consider eating off plan. As long as you keep carbs low enough, you will probably not see numbers anywhere near that range. But you've got to keep your carb numbers within your personal carb tolerance and you've got to be consistent. You might want to start testing blood sugars after every meal to determine what keeps them stable, what send them up.

You are very strong to face this head on.

One other note, I see you are on CAD. That may not be the best plan for someone with unstable blood sugars. Have you read Dr Richard Bernstein? He's a type 1 diabetic himself and has a great plan for stabilizing blood sugar.