A mitigating step you can take is to exercise and get your heart rate up to the zone for twenty minutes after each meal. If your body has figured out a way to become more insulin resistant, you need to retrain those mitochondria. It won’t get to the bottom of why the sudden change, but it should drop your BG numbers and you should start feeling better. Also, if you can take steam baths every alternate day, that will help reduce the serum glucose. Good luck! Let us know what you experience and find out. I also agree with others that you need to get in to see your doctor. You could be a type 1.5.