All good advise.
Be well.
I agree with what super Sally wrote. Best option is to eat a low carb, moderate protein with balance of calories from fats, like olive oil, nuts, grass fed butter, etc. not sure beans and lentils are good for you, as this causes increase in sugar in blood from high carb content. Also don't be afraid to eat fats. People who eat low carb with ultra high protein and low fat run into the gluconeogenesis problem, which is your body taking some of the ultra high protein intake and making sugar (glucose). This is why some people get high blood sugar and heart racing after drinking a large protein shake (with low carb and no fat). Eat fat with your proteins, like full fat yogurt. Eat three meals per day, no snacking in between, and typical meal looking like this: green or low-sugar vegetable with meat/flush/eggs and healthy fats (olive oil, coconut oil, grass fed butter, avocado, nuts, etc). Stay away from carb rich stuff like beans, rice, pasta, bread, flour, etc. stay away from sugar. Eat fruit as a rare treat, opt for vegetables instead.
Well consider a work up by a doctor that specialize in "functional medicine". They are going to look at everything. You can google one in your area. Your problem could be anything e.g. thyroid condition, low vitamin D3, etc. etc. etc. A good doctor can really evaluate all these things.
I say D3, because a friend of mind kept fainting. They did all kinds of tests and couldn't find anything. She finally went to a functional medicine doctor who was saw she was low on D3. She started supplementing and her fainting spells went away. It was miraculous.
Also, you may not be able to do a traditional glucose tolerance test, but you might be able to do a carbohydrate challenge test. A carb challenge test can give a doctor a lot of information and at the same time not be so hard on your body.
If you get one insist on a 4hr test. Also insist that they measure your insulin levels at 1/2, 1, 2, 3, 4 also.
Also, try to calibrate your glucometer with serum test. Your glucometer could be off. Some of them can be off by as much as 30+%.
Be well.
Your blood sugars are abnormal.
The best and most cost effective way to manage blood sugars is by eating a low carb, moderate protein, high (healthy) fats diet. Combine this with exercise and normalize weight if overweight.
The fats and protein will slow down absorption of carbs and help to prevent high blood sugars.