Hi Anticarb, re: your manager's meeting, do you have on-site catering or is the food from an external company? You could tell the person ordering the food that you have developed a sensitivity to bread, so could you have salad instead (some people will be jealous of your salad and will say 'oh I wish I had ordered that', and next meeting I bet there will be a mixture of salad and sarnies). I'm not always comfortable with telling people I have diabetes, especially in a work environment, so I say I have a gluten intolerance or that I am dieting. You could also ask for fruit snacks along with the donuts/cakes, at least then you have the option to make healthy choices, except that other people in the meeting will nick the fruit and leave you with the cookies.
I too am an all or nothing kind of person so I know exactly how you feel, once you start on that stuff you just have to keep going, but if you have the option to eat other stuff then you probably will. I always think of how much exercise I will have to do to offset the bad stuff and how much its going to hurt, and that I could be losing weight instead of fighting off what I ate today. Anyway, good luck