We are doing this now. We've had our GD diagnosis for about a month and it's super lame. We failed our 3 hour by just 3 points...I almost made them re-administer the test but when I started tracking my blood sugar I realized I could use the education in how my body works anyway.
I believe you are, in fact, considered high risk with a GD diagnosis. At least, with my first baby if I'd failed I would have had to stop seeing my midwife. (I passed the 3 hour that time.)
Now, with our second, I didn't pass. It's not fun at all, but ours is really well controlled just with diet and exercise. We saw an educator who helped me work out a meal plan (read: how many carbs + protein to eat at each 2-3 hour interval) and how often to test (4 times a day in our case). She recommended walking for 10-15 minutes after each big meal instead of doing one big session a day because that can actually spike your blood sugar. Go figure.
Depending on how strict your doctor is should you be gestationally diabetic, you'll need to stay under a certain blood sugar level or they might look at putting you on insulin. My doctor is pretty comfortable with my numbers and she doesn't freak out if I have a couple spikes, especially since I can almost always identify the source.
The hardest thing for me is the emotional side. I feel guilty that I "let my baby down" - even though my family is diabetic on both sides and this was probably just the way the cards fell more or less. I also get frustrated when my husband wants to go out because I have to do a lot of research before heading to the restaurant - but it CAN BE DONE. Really, though, I'm trying to focus on how much I'm learning about my body and the way it processes certain foods. For example, sugary foods don't really cause a spike but fatty ones (like peanut butter) I'm crazy sensitive to.
This information will help us stay on track after the baby is born (3w2d from today). And in almost all cases the diabetes goes away almost immediately after birth - I'm told.
Hopefully this helps, but I would say for now focus on passing your three hour. Many, many women do and there's a good chance you'll be in that group. Good luck!