I would like to say that just because you are overweight does not mean you will have GD. Iwas (and am) morbidly obese with both DD and this one. I had 2 full 2 hour glucose tolerance tests (the two hour ones) with DD and aced them both, and I didn't put on excessive weight either. Where I worked I saw the full spectrum of women with GD, from super skinny, super fit to people like me. Just because you are at higher risk doesn't mean you will develop something. You are eating well anyway and exercising so just relax and enjoy your pregnancy, and don't be scared of the insulin test.

Good Luck!