If you are doing NHS guidance diet then you'll likely need to think again with it! They recommended I ate cereal for breakfast and that stuff is full of sugar! They generally just give you the advice they'd give to a newly diagnosed type 2 diabetic who has space to do some trial and error with food and has higher targets. With GD you need to get on it quickly to protect your baby.
Have a look at GDUK. There is info there on how blood sugars work and how your body will spike with high carb foods. Any spike means excess sugar going into your baby.
You won't miss out on stuff but you need to eat cleverly. So the sort of things I ate were strawberries with double cream and chopped nuts, granny smiths apple dipped in peanut butter, boiled eggs, a freddo with loads double cream and nuts, double cheese and ham toasties with brown bread, pizza made with brown wrap and loads of cheese and pepperoni, fry up of bacon, egg, high meat content sausage, I did switch to brown pasta/rice etc... I ate veg from above the ground as they are generally lower in carbs than those grown below.
Plenty of food, in fact I are constantly to avoid throwing up! And you can eat ALL the cheese with GD. Like, I ate two blocks of cheese a week!
And also just to add, GD is nothing you have done, it's not about your weight (Cheryl Cole had GD when pregnant with Bear!), It's not about your previous diet. It's a pregnancy complication same as any. It just needs to be treated through diet/tablets/insulin and it will go away once you have the baby.