Aaah, that explains part of it. What you are experiencing could be a "false low". When you have been used to running much higher (and you have, not that long ago) your body gets used to it. And close to normal numbers will make you feel hypo (sweaty, nauseated, shaky). The good news is that this goes away with more consistent control. Keep at it. Try eating something like nuts or cheese when you feel this way. It can help but the no/low carb food won't raise your glucose.
To my mind, your doctor is on the money. An a1c of 11% translates to an average glucose of 269. So a lot of the time you are even higher than that and you have probably been running that high for quite some time. Significant damage is occurring and the sooner your sugars are under better control, the better. Once things are better controlled, there is always the possibility of stopping the insulin. But you can't take back the damage. It can take 6 weeks or more for a drug like metformin to take effect, but th einsulin works fast. That's my take on it anyway.
Are you also cutting carbs and exercising more? Also, have you been tested for type 1? That is always a possibility too. What is your insulin regime? Just long acting or short acting before meals as well?
Anyway, it seems to me that your doc is concerned with preventing any additional damage and is looking at your long term health.
Glucose levels are not age related. There is normal, and not normal. Less than 99 fasting is normal. My Dad is over 80 and his last fasting glucose was 76. At 120 you have what is called either "pre-diabetes" or "impaired glucose tolerance". Since you are only 68 there is still plenty of time to develop full blown diabetes and complications if you don't nip this in the bud now. You can do this by cutting carbs a bit and exercising more if possible.
As for how you "feel", I'm sorry to say that is irrelevant. Diabetes is like blood pressure. It is a silent killer. You can feel fine right up until the point where you no longer do.
But if you don't believe him and the "common wisdom", that is your choice. I believe it is always better to err on the side of caution.
An a1c, aka hemoglobin a1c or hba1c, or glycocylated hemoglobin test is given as a % in north america. What happens is that naturally, the glucose in your blood sticks to your hemoglobin cells. The higher your blood sugar, the higher the % of hemoglobins that have sugar stuck to them. You can then calculate and convert this % to an "average" glucose level. Individual finger sticks tell a story of how you are doing, but an a1c will give you an average of over 3 months (roughly the life of a hemoglobin cell). it is more heavily weighted for the last 6 weeks.
Since you can't test every minute of every day, the a1c can give you an idea of your overall control. But it isn't the only thing to look at as severe lows, and short term severe highs won't really show up. So finger sticks plus the a1c give a good overall picture.
Pretty much any sort of tortilla will have carbohydrates in it. How it affects you will be different from anyone else. The only way to know for sure is to eat a known portion, and then test at the 1 and 2 hour marks to see what happens to your blood sugar.
I hate to be such a downer steve, but the development of complications due to high blood sugar (which you have) does not come with symptoms. Until you have problems. As it stands, your muscles are not helping to burn off enough glucose. The "cut off" for a safe a1c has been determined to be 7%. And you are over that. It is possible that with some changes (as I said, meds or diet), you could get things under better control to be safer. Then work more on the muscles and back off on the meds.
Just my opinion. I would hate to see someone have to go through what I have been through.