Been there, done that. :) My Dr was out of Big Baylor so I went to the same diabetes center. It was a positive experience. I was in total denial and was kind of angry that I failed the test. The nurse assured me I was not the first one to go through this.
In the scheme of things, it's a very manageable thing to get -- way better than something like pre-eclampsyia which cannot be managed by diet or insulin. I was a good girl and kept records of all my blood sugar levels, ketone levels and what I ate. I didn't eat any artificial sweeteners (hate them personally) and was able to work in my daily chocolate. My pregnancy was pretty uneventful. I did end up with an induction (and subsequent c-section) at 38 weeks. I caught a cold around 36 weeks and my blood sugar got a little out of whack. Rather than deal with insulin, my Dr just had me hang in until 38 weeks. The good thing about having GD is that you get a lot of attention and ultrasounds in the last trimester.
You'll get the hang of what sets your blood levels off (for me it was things like french fries) and what combinations work (proteins help keep your carbs lower).
The diabetes center will give you a meal plan to work with. You'll meet with them individually and may also meet as a small group. They'll tell you how many carbs you can have a day given your weight/height/etc. It's not bad. Don't think diet as in nutrislim or anything. I actually ended up eating ALL the time on the diet. It's not like a starvation diet by any means. You just need to be aware of how many carbs you are taking in each day.
You'll need to test yourself several times a day. That made me a little nervous, but working with the nurse it was no big deal as it turned out. Once you do it the first time, you realize that it doesn't hurt. (This was 5 yrs ago so those meters have improved btw). I also had to pee on these little sticks every morning to make sure I got enough carbs. If you get too many carbs, it makes you sleepy and isn't good. If you don't eat enough carbs, it's really really bad for you and the baby. The key is balance.
As far as how to eat right now, just keep doing what you're doing. A week isn't going to make or break you at this point; however, once you do get your meal plan stick to it religiously. Don't give up all carbs, because that's bad too. Keep in mind, carbs are found in more than just bread or pasta -- things like potatoes, peas, corn, fruit, etc all count. Maybe try upping your protein intake. Veggies are typically low on the glycemic index so you can pretty much (with a few exceptions) eat a lot of these. I could tell if I had too many carbs if I got sleepy after a meal. Of course, with an older child you probably feel that way already even without the food.
Good luck!!