Did your OB not give you a diet to follow? I would think they would be very specific about your diet, and portions, etc. I had gestational diabetes and was sent to a dietician who made it very clear.
Best wishes -
With diabetes you have to watch your Carb intake. Most veggies are low in carbs. Potatoes and corn are high. Fruits are high in carbs. Your meats are low in carbs. Watch what you out on your meat though because most sauces are high in carbs, like BBQ sauce. Watch your juices they are high as well. I take care of a lady that has diabetes and with her she is allowed 40 carbs per meal. If you just watch the Carb in take you should do really well.
Watch your carb intake as well that will shoot it up