Just because you failed the first one doesn't necessarily mean you have g.d. But the three hour test is a pain in the butt, so I can see why you are frustrated. I don't know why you don't think you could keep your son entertained for three hours...ha!
Just a warning on the three hour test though. I felt pretty crappy after mine...that stuff you drink and then waiting that long to eat, it just did something to me. Make sure you take something with you to eat so you can shove it in your mouth as soon as you are done. Something kind of bland.
And don't beat yourself up too much about what you are eating. Most of us do that here and there, and you could have been eating a stellar diet and STILL have failed the test. Maybe you just had a weird spike in blood sugar that day too. I'm sure you already know how to adjust your diet to help...lots of protein and veggies, less carbs. Here's to hoping you don't have g.d. and you pass the three hour test with flying colors!!