Looking for information for the possible causes of high fasting blood glucose, but no issues during glucose tolerence test.

My doctor is negligent and dismissive of my concerns of high fasting blood glucose(104-115), but no issues with my glucose tolerence test. My h1a1c is 5.4, but it used to be 5.0, so its going up. I am healthy weight and in fact never been this slim.

I am deficient in iron and read that can impact glucose metabolism.

Any other avenues to explore?

Thanks.