That situation sucks! I know she was just looking out for you but to announce it in front of everything was wrong.
I would vent as well. I probably would have also said, I may have GD but another side effect of watching your sugar is low blood sugar. Candy especially hard candy is one of the fastest ways to bring it back to a safe level.
If it is still bothering you after a couple of hours, I would have an honest conversation with your boss that while you appreciate the concern you would prefer all medical conversations or comments happen behind closed doors.