Any diabetic diet is similar to the GI diet. You need to eat complex carbohydrates inplace of the simple sugars. Basically white rice, pasta should be out of the equation replace all of those with a brown version, sweet potatoes/yam are better for you. Good fruits are apples and berries. Watermelon is very sugary surprisingly stay away from them.
Breakfast should be whole grains, natural yoghurt, eggs etc
Main meal - Your dietician will tell you how many calories to eat each day. She will show you a medium sized plate and tell you that half of that should be veg or saladthen about 2/3 of the remainder should be complex carbs and the left over protein.
Milk is high in lactose so don't frink loads of this either.
Swimming is a good way of raising your activity level when pregnant, and this will help keep those insulin recpetors in check.
BAsically, you need to eat 3 medium meals a day, and 3 snacks, all avoiding simple sugars.