Its a very good idea to get an A1C, if it would be me I would insist on a glucose tolerance test, as it is the only way to really know if you have pre diabestes or not, I had an A1C level of 5.5 which is considered normal level but that was only because I was on a low carb diet, when I monitored by blood sugers for a few days I realized my levels really go up, so I am on Metformin and a very low carb diet and feeling great!
If you feel tired after eating it is a very good idea to go see an endocronologist to see exactly whats going on, fasting levels should be below 100