Yes, a gluten-free diet can seem overwhelming at first. About 10 years ago I started having major acid indigestion, and it took a while to realize that it really flared up when I ate wheat. So I started researching and found information on celiac. And I felt sorry for myself for the first few months, until I realized that there are far worse health conditions to have than gluten intolerance (I'm not going to die because I've eaten a trace of peanut for example).
One of the things I learned is that there are lots of other foods that can take the place of the wheaty starch portion of a meal. There's rice, of course, and quinoa and amaranth and beans and buckwheat and corn.
I would suggest that the first thing is to figure out which things you miss the most and see if you can find substitutions for them. You might need to look in a health-food store or in a well-stocked supermarket, in the dietary section. Look for products specifically labeled "gluten-free". Then you might start expanding your cooking skills.
The reason that Pizza Hut can't offfer a gluten-free pizza is that there is no way to keep it from getting contaminated by the wheat flours that are used by the "regular" pizzas. There is flour all over the kitchens, and flour in the ovens, and flour on the paddles that they use to take the pizzas out of the ovens. Any pizza that started out gluten-free would be contaminated by the time it was delivered to you.
I have a couple fo suggestions. First, there may
be some ready-made frozen pizzas specifically for gluten-intolerant people (I live in Germany so I don't know what is currently available in the U.S.), and you may find them useful as a last resort. The problem is that they are made to be eaten by people with various dietary restrictions, and they often have no egg or milk products, and they're dry as a bone. Another option is to purchase gluten-free pizza-crusts in packages from the shelf, and put your own toppings on them (tomato paste, veggies, salami, grated cheese, etc), and cook them in your oven. My husband has been very patient eating my cooking experiments, and is pleased that I now have a recipe for a buckwheat crust that that tastes like a whole-wheat version of a real pizza. The key to making home-made pizza is to get a pizza stone that you can preheat in your oven, and slip the pizza onto it to cook. This gives a wonderful crust that cooks quickly and tastes much more like a Pizza Hut pizza because it's baked very hot and quickly from above and below.
My suggestion is to make this a family adventure. That is, don't focus on what y'all are missing and deprived of, but on what new recipes and products you can discover next. Make a list of the family's raves and hates. I discovered that quinoa tastes yummy and millet tastes bitter. Your family's list will be different than mine, but it will be fun trying different things.
One of the things that finally brought me out of my self-pity was the realization that most of the things that I missed are not good for me anyway. Wheat is everywhere in the western world because it's so easy to use. This allows manufacturers to produce an unending supply of things made from white flour and corn sugars and preservatives and all sorts of other chemicals that have no nutritional value at all except for the calories. By realizing that I was going to have to learn to cook with unfamiliar ingredients, I realized that most of these unfamiliar ingredients are far more nutritious than white flour.
Another thought that occured to me a few years ago is that it actually is an advantage to be able to say at a party "thanks, but no thanks". I have little will power, and love to dive into sugary goodies when they are offered. But gluten makes me sick. So my gluten-intolerance allows me to say no to unhealthy food. I am not deprived of sugar in my life. I put sugar in my tea and on my cereal in the morning. I can bake at home and I have developed recipes that are so good that my friends actually ask me to bring them to parties.
I have learned to look at my blessings in life. At parties I can bring something that I know I can eat. I can concentrate on chatting and having a good time with people that I like. My life is not poorer because I can't eat the cakes and cookies and other empty calories. I have friends. I can laugh. I can share the human side of things. I am not deprived.
This will be more difficult for your kids. But they can over time learn the same lessons. Friends are important. Pizza Hut isn't.
Go ahead and feel sorry for yourself and your kids. I did.
But then make a big sigh and look at this as an adventure.
Let us know how your doctor visit comes out. And keep us posted on further challenges and questions. We can all learn from each other here.