Plus we are nearly to the shortest day of the year, where everybody tends to be light deprived in the Northern Hemisphere.
Once you get the diet figured out, you will feel better, but there is a learning curve.
Try taking a gluten free multivitamin, a B complex, and a calcium D magnesium mineral, because malnutrition can also cause feeling punked. Also, make yourself exercise, even if it is just for 10 or 15 minutes a day. Play some happy music. Go for a walk. Do something new you've been meaning to try. (and if you're wondering how you can do this with symptoms, I am stubborn enough that I will eat a safe gluten-free meal I make myself that I know will not bother me, then just not eat again until I get home, if there is something I really want to do. But I always carry my own water bottle and a safe snack when I go anywhere. ) You may want to check out the specific carbohydrate diet, or SCD, which is a high protein, high fat, no grain version, that you can eat for a while to get it under control and then branch back out into re introducing grains again. They use ground nut meals like almonds, which are easily digested, to make bread/cake/pancake products. They also call for a lot of yogurt, but you don't have to do that if you are totally dairy intolerant. Have you tried canned coconut milk ? I can make a bowl of gluten-free nut meal bread in the microwave in about 5 minutes - including grinding the almonds in the blender, but I've got a lot of practice.
People vary in sensitivity, also. I am not that sensitive to cross contamination, I suspect, compared to some people. I can eat out at restaurants that have a gluten free menu offering or will attempt to do one in good faith. Hint: never do this the day before a Major Holiday or Activity, just in case they screw up anyway. We ate out last year or the year before, (it blurs, but I can tell you exactly what the weather was....) on Christmas eve at well known chain restaurant with good reputation, off the gluten free menu, and I got as sick as a dog the next day, and then couldn't do anything but lie in bed. So there went our planned holiday day trip. This was an anomaly for that restaurant, why I'm not naming them, and for my reactions. We've since eaten at lots more restaurants, off the gluten free menu, and I've not ever had that problem like that. But at first my diet was very, very plain (to most people) and low carb.
Come New Year's, and my darling spouse proudly brings me some commercially made Gluten Free Chips, with a lot of seasoning baked in them, and I react again. Oh, goody ! I eat rice crackers and corn products all the time. This was a different brand.
I swear I'm going to just mash an avocado this year and eat it off the spoon. I'm gonna grow the lemon and pick it, too.
You may want to try an elimination diet and just eat plain fruit, vegetables, meat, eggs, nuts, and olive oil, and see what happens, if you feel better or not.
I have had some off reactions on food we have made at home, from manufactured ingredients, and have found that if I search here for a product review it will be likely revealed I'm not the only one. I stopped using boxed gluten-free milk substitutes in baking and now use just water or egg for the liquids, after ruining a big batch of baked goods, with something that was labeled gluten free, but wasn't completely. That was exasperating and expensive. My spouse, who is very vigilant, has also gotten me a few times accidentally when cooking- but at a restaurant, he's also caught the wait staff before they give me something they shouldn't, by asking, "and that's the gluten free version, right ?" We recently had to toss a new bottle of garlic powder which I was reacting to - name brand, but had "ingredients from China" on the label. Three times he had put the stuff in scrambled eggs and three times I felt puny afterwards. And people can hate it when you are really watching their every move in the kitchen, ready to pounce.... Imported msg can also now be contaminated... like I said, it's a learning curve.
Oh, and your relatives won't mean to, but they will get you. I've done restaurant cooking, I've done this gluten-free thing for years, I sort of understand "germ theory," we don't have gluten in the house, and yet, I don't know if I would attempt to feed somebody else gluten free. The average person, on the other hand, has no idea what the heck they are doing, nor how to read the labels, nor to use a dedicated pan without old residue. Or they don't think, and double dip the spoon or knife into the jar and then wipe it on a gluten item first... they may have baked before, and contaminated a lot of the other ingredients with wheat flour... where has that towel been... what was in the tupperware last... They really mean well. But, Oh, Good Grief.
Pets. Life is simpler if Kitty is not eating wheat, rye, or barley, either. Trust me. If Kitty sleeps with you, or hangs out on your desk, get the wheat, rye, and barley free cat food, because they lick themselves and then shed the dander and hair everywhere. I have the dogs on gluten free also, but I have 2 dogs who are massively allergic to it, so that must be somehow why they ended up here in the Karma of the Universe. You do not want to see how the dogs react to accidental wheating, which involves puking and peeing on the rugs. My one dog goes completely OCD. My cat was drinking out of the dog's water bowl and cross contaminating the dog.
Don't obsess over the weight thing. There is a lot more to life than being stick thin, like being healthy and happy.