I started going gluten-free (not just wheat, this includes barley and rye) solidly a few months ago in an attempt to reduce my body's immune system issues (including psoriasis, arthritis and the aforementioned mid-afternoon slump in energy). When I stick with it, I definitely feel less pain and ache in the joints, and more energy. The psoriasis has eased, although I'm pursuing other therapies simultaneously so perhaps one or more of those are helping as well.
My biggest challenge is the bread. I make four loaves of sourdough white sandwich bread weekly for our family (big sandwich/toast eaters) and it can be agonizing to watch my boys butter up a nice thick slab of sourdough while I'm gnawing on my measly little slice of Udi bread. I've tried a few different recipes for basic gluten-free yeast bread, but without much success. It's a process...
Costco has just started carrying a gluten-free pasta that is wonderful. We eat a lot more oats, rice, and quinoa now as well, and instead of cookies I've been leaning towards snacks like popcorn and nuts. I make our own gf granola that has been quite a satisfying substitute for cereals. I'm ashamed to say I drank several beers before the penny dropped about the barley, d'oh!
There are a few good all-purpose gf flours out there (my supportive mother-in-law send a package with three or four different ones, which I called my "bouquet of flours"

). I do not recommend the
Authentic Foods version (gritty and odd flavor); the
King Arthur and
Bob's Red Mill were both good but do not include xanthan gum (a necessity to get good results with gf flours); the
Arrowhead Mills version was also good AND included the xanthan gum. I did buy some xanthan gum, so I can use all of these now. They all are fine substitutes for flour when making a roux, biscuits, muffins, and cookies... I just don't have the bread figured out yet.
I haven't been super-diligent about things like salad dressings and eating at friends' houses... if there's flour in a sauce, I've been letting it slide. I have to wonder if that would make a difference, but I'm anxious about not becoming a super-picky, needy guest...
If I have a slice of bread or half a bagel (Chouxfly's baking is not to be snubbed), I wind up taking a two or three hour nap. I'll do it once in a while when I know I can afford the luxury of sleep, but it's a pretty strong reminder of how I used to be and a good motivation to continue avoiding gluten in the future.
It's very interesting (and validating!) to hear about others' experiences going gf; looking forward to hearing more from you all.
ETA: To answer Toria's question, well, I can't answer it and I'm not sure anyone else can, either. Every body is different, and there are so many factors that could be part of your pain. I've heard of people having decreased inflammation on gf diets within a week; others who have taken up to six months to really have solid positive results, especially with issues involving a chronic condition like arthritis. I hope you're one of the lucky ones!
“Assuredly it is a great accomplishment to be a novelist, but it is no mediocre glory to be a cook.” -- Alexandre Dumas
"I give you Chicago. It is no London and Harvard. It is not Paris and buttermilk. It is American in every chitling and sparerib. It is alive from tail to snout." -- H.L. Mencken