What is wrong with me?

It sounds like you had a thorough evaluation by your health care provider. Unfortunately a proper diagnosis is difficult to find when a patients symptoms come and go. It's almost like to need to to very sick consistently before lab work becomes abnormal and they can figure out whats wrong with you. For a flushed face and intermittent "brain fog" I would try to watch your carbohydrate intake . For the next 2 to 3 weeks avoid heavIy carbs such as anything made with white flour, corn , potatoes, and cereals, rice, and of course white sugar. Limit fruit to one per day. See how you feel after this time. If you notice that you feel alot better, you may have some potential for diabetes in the future if you continue eating alot of carb.. I have had similiar symptoms as yours and the brain fog is really bad when you get lost driving, and cant function at work. Try this suggestion and I hope you will feel better. Namaste