Four years ago I was in the EXACT same spot, I got diagnosed in my mid-40s. I lost lots of weight and had no idea what to eat at all. I was starving. And little or no alcohol for six months since the intestines were injured. That was real tough. What to drink/not drink is a whole other thread...but on to my very first gluten free diet from the first days and weeks:
Breakfast--gluten free cereal (lots of the Chex are gluten free now) with sliced bananas because they're more filling. I couldn't do milk at first, so I used soy milk at the time. You get used to it. Scrambled eggs and a baked potato (believe it or not). I was too lazy to make home fries.
Lunch--tuna or gluten free lunch meat on gluten free bread. Goodbye Gluten (believe it or not) is about the only gluten-free bread I can tolerate taste-wise...but know that nobody's really gotten gluten free bread close. I gave up on frozen gluten free bread since it would disintegrate as soon as it thawed. You can throw in a fresh ingredients salad with gluten free dressing (lots now, look them up by brand). I did lots of salads with canned tuna in them.
Snack--my first post-celiac snack was Nestle's toll house semi-sweet chocolate chips (most are just now being labeled gluten free, check closely on the back) and Diamond Almonds mix. Most Diamond nut products are gluten free, look that brand up too if you like nuts. I had to gain weight back, thus the nuts mixed with chocolate for my sweet tooth.
Dinner--Broiled or baked chicken breasts, fish, pork...all the raw stuff you cook yourself. Steaks and baked potatoes with gluten free margarine like Olivio or real butter (look up your brand). Steamed raw vegetables or from frozen (the plain, frozen vegetables).
Progresso has labeled soups gluten free right on the front or the side of the can (in smaller print with some other facts). There is "gluten free" Mac and Cheese made by Annie's I think it is.
A note on meats...DON'T get any meats that say things like "up to 12% solution" or whatever. Economy grocery stores carry those a lot, so steer clear there. BUT at the same time there's a store here called Aldi's which is an economy store but labels TONS of their regular products as gluten free, I've seen the labeling almost double it seems in the four years since I had to start gluten free myself. If it says gluten free, you are good to go.
YOU WILL GET THIS DOWN...trust me and after awhile it just becomes regular. No, you can't go out to eat many places like you used to because you've gotta get gluten free...but there's more places than ever before with a gluten free menu and you can go there ONCE in awhile. If you're not negative for active celiac yet (the <20 Iga reading) DO NOT take chances. Your life truly depends on stopping the active celiac condition in your gut but it CAN be done...but you must eat only whole foods or goods (think the "perimeter" of the grocery store) OR gluten free labeled products. It blew my mind the first time I walked into a grocery store and realized I couldn't eat most of the of the stuff in there. I never gave it a second thought. Now I don't even think about that anymore, and just go for the stuff I know I can have and the mind-blowing is in the past.
One of my first celiac tricks was...if I wanted to know if I could eat something and it wasn't labeled, I would need to see three sources that told me it was gluten free: these boards, manufacturer's website and a third place like gfoverflow.com. If I got three "yes" answers for gluten free then I could eat it. For example, Heath bars (my weakness).
After awhile, you will have quite a regular and full list of "safe" foods. The hard part is passing up most things everyone else eats (even with the family...they'll have to accommodate you there) and sticking to what you KNOW you can eat. No guessing, because there is no cheating. Your intestines have been injured and have to heal. And the WILL heal and stay healed with gluten free eating. But you can't cheat, you'll get sick all over again and you put yourself in a high risk category for really, really uncool illness.
It was hard as hell for me, I hear ya. But like anything new you will question, learn, assimilate and incorporate it into your daily life and routine. You are now the FIRST source and LAST word for celiac among your not-understanding or even well-meaning friends and don't be afraid to be really on top of it. Get these good habits right at the beginning and honest, with time it's like driving a car. Second nature.
Not second nature now, but it will be.