You should test a fasting rate first thing in the morning. (no food after midnight). This will show if you are having too much insulin (if very low) or if your liver is starting too much gluconeogenesis just before you wake up. Do a fasting every day for a week and see what dinners the night before affected.

Sometimes prediabetics show low readings at first (except for perhaps the fasting morning one) for a while. This is because you are making MORE insulin than you should. These lows are really also bad for the nerves.

None of your readings can be considered accurate until you calibrate that machine (testing solution) and strips.

When you are prediabetic the HbA1C is a very good indicator of overall risk of diabetes. If it is over 7 and you are 60 and above, that is the start of type II.

There are other food things that can cause burning in the hands/feet.
1) gluten intolerance -- this can be acquired, and is insidious and complex.
Avoidance of wheat, rye and barley in everything sometimes helps. We have a Gluten forum with information at the top of that page.

2) some people have food intolerances. The biggest for me was Nightshade vegetables. I cannot really tolerate potatoes anymore. I get burning the night of the day I have them. I still cheat now and then but 90% of the time I am potato free. Some concentrated tomato sauces will do it to me too, but not all of them. Each person may have some food issue: eggs, chocolate, soy, dairy are all potential culprits. The only way to find out is to do an elimination diet, remove one group for a month, and reintroduce it and see what effects if any there are.