What are the dosages, frequencies, and brands of supplements that you're taking?
Wean off and stop the troublesome supplements you suspect for a week. Take only ONE of the potential supplements that might be causing your symptoms. Experiment.
Info about A1C accuracy.
"Most doctors who screen you for diabetes give you a fasting glucose test or an A1c test--though the American Diabetes Association specifically states that the A1c test should not be used for diagnosing diabetes. But research published in 2008 that was based on studying a group of 2,442 subjects who were free of type 2 diabetes at the beginning of the study found that fasting glucose tests were a very poor predictor of who in this group would develop diabetes."