Diabetes is not a death sentence unless you don't take care of yourself. Diabetes is not curable, but it is certainly treatable and you can life a long life if you take care of yourself. (My mother lived for over 40 years as a diabetic.) Your doctor will give you instructions and all you need to do is follow them. If overweight, you'll need to lose a little. Cut out/down on white bread. Exercise and more exercise. I still eat pastas (whole wheat) and pizzas, I just don't eat them as often. Go the the American Diabetes website and do some reading and I think you will feel much better.
Good luck.
Look around for diabetes support groups and see if you can join one. Having others around you that are going through the same thing or similar to you can be a great help.
Next, start taking care of yourself. Listen to your doctor's advice (I'm bad at that myself!) and follow your diet, keep up on your excersize and take whatever meds you are put on religiously. Lastly measure and keep a record of your blood sugars. Knowing what your blood sugars are doing is a Godsend as far as I am concerned. Some meters actually internally graph your measurements and can be downloaded from so your doctor can have something to look at during routine visits. Trending is a plus.
Don't despair. At 30 your life is far from being over. Your gonna die, but it might take 40, 50 or sixty years for it to happen. :-)