Hi cueball - I'm so sorry you feel so bad, and I am writing a long post because I do relate. You sound very depressed, and that is why I think maybe you have a gluten intolerance or celiac, like I did. I've written about these things before - but they're archived, so here goes…
I agree with Jocelyn that PT will help you a lot. And, I agree with kvc that weight is much more complicated than diet and exercise. I think it has to do with your biochemistry. I always gained weight on certain medications, and dropped it when I stopped them. I am now healthy weight, don't diet and don't exercise (though I am trying to start).
I'm not sure if my pain was like yours - no sunburn feeling - but I felt like I had a bad flu every morning, ached all day and was exhausted. I also have bone and spinal problems (and those ARE getting worse with age). However, I was able to rid myself of the "fibro flu" pain, AND depression, AND GI problems, AND extra weight (you mention all of these), AND strengthen my immune system. My blood tests had shown inflammation markers, high sugar and cholesterol. Everything normalized. Even though I eat all the sugar I want, my glucose reading was lowest it has ever been! Here's how I did it.
I read an article about a man with chronic pain, a 30 year runaround - diagnosed with everything up to bone cancer - but he really had celiac disease. 97% of celiacs are undiagnosed, and testing is unreliable. Doctors are ignorant about it. Estimates are that 1 in 7 has some kind of gluten intolerance and 1 in 133 has full blown celiac disease. For more information, I recommend the excellent book "Dangerous Grains," which you can google online. Also google "celiac disease," but the usual medical sites are unreliable, read the forums. (Celiac disease is an allergic reaction to gliadin, a protein found in cereals, in the small intestine - it gets inflamed and irritated, just like your skin would if you had a bad scratch or sore on it, but you usually have no awareness of this.)
I went strictly gluten free, and kept a diary. ABSOLUTELY NO wheat, oatmeal, rye, barley or other cereal grains. (I eat tapioca, corn, rice and potato and their flours, and meat, eggs, fruit, and veggies.) My pharmacist ensures my meds are gluten free. I read all labels, and avoid boxed or bagged food because of ingredients like "starch" or "flavorings" -- in fact, I whip out my celphone and call the company to check - and complain if they have no gluten-free choices! No more dressings, sauces. Most soy sauce is made from wheat! No more Chinese restaurants. Some root beers have "starch" in them! Read ALL labels. If I go out to eat, I tell the manager I need gluten free, and get simple meat, baked potato and veggie. Keep it VERY simple because a lot of places will lie about being gluten free when they're not. (People don't understand the diet.) If I get gluten, I hurt, sleep a lot, then get very depressed. It takes a month to feel better. 1/8th of a teaspoon of flour can cause a problem for a celiac! So if I have a salad, and there is one crouton in it by mistake, I'm in trouble.
It took about a year - and that included setbacks due to getting gluten by mistake. Then I realized my aching pain was gone! After a couple years on the diet, I saw a famous (Italian) celiac specialist. My blood test was negative - because I'm gluten free. He told me I would have to eat gluten for 3 months to get a diagnostic blood test -- No Way!! When I look at bread, all I see is PAIN. However, on the basis of what I told him about my response to the diet, and all my clearly improved bloodwork, he diagnosed me with celiac disease.
Depression is the PRESENTING symptom for most people with celiac. And you seem a little depressed, cueball! I'm glad you have not taken antidepressants, because they can be very nasty drugs and withdrawals are awful! I hope you will give the diet a try - it might work miracles for you! Find a good nutritionist or alternative doc to guide you.
Doctors are ignorant about this disease. It has not been taught in medical schools, it is barely mentioned as a "rare" disease, considered a disease of childhood, with diarrhea and failure to grow. It is usually never diagnosed. If you have it and continue to eat gluten, you open yourself up to many serious diseases as you age, due to malabsorption - the book Dangerous Grains discusses all that. Gluten intolerant people often need to supplement with extra vitamins and minerals, as kvc said. If I don't take my minerals, I get severe muscle cramps.
I now eat ALL I WANT -- but I'm not that hungry. I think if you have celiac, you get addicted to wheat just like an alcoholic - it's bad for you, but you crave it - donuts, bread, cake - you have to break that addiction. Also, I suspect you are very hungry because your body is starving and is not able to absorb the "right" nutrients. For that reason your gut is immobile, your body is hanging on to everything, extracting whatever it can - making you fat, but not well-nourished. (Just my opinion on that!) Good luck to you. Hope you feel better.