First, welcome - this is a great place to get support and motivation. Try to visit as often as you can.
Like you, I was overwhelmed. I have a lot of physical problems due to my weight - All the things you've described in your post, I've experienced too. Most of us here have. I have high blood pressure; I have heart disease now; I walk with a cane because of back and leg pain and I have to use a wheelchair when I go to stores because I can't walk or stand for more than 5-10 minutes. I could go on and on.
Diets - Name one and I've been on it. Name 30 and I've been on them all. They work for a while - then I "fall of the program" and regain the weight, then try another one.
I got to the point I gave up. I cannot follow a structured diet plan. But I know what's considered "healthy eating" -- we've all seen pictures of "The Plate" sectioned off with something like 1/4 meat, 1/4 carbohydrates, 1/2 vegetables/fruit -- and a small sliver of fat. We all know we're supposed to drink the 8 glasses of water. So what I do now is try my best to eat sensibly. I try to aware of my hunger and eat when I'm hungry - not out of boredom or frustration. I do my best to eat healthy and avoid fried foods and sugar-loaded foods, etc. Although there are times I occasionally have fried chicken or pizza -- but it's only occasionally and I don't feel guilty about it. I drink water all the time and avoid sodas and other sodium-loaded food.
And that's what's working for me. I'm losing weight without stressing out. I plan to eat as healthy as I can. I don't formally count calories, but I know by eating healthy I've cut down on my calorie intake - it just makes sense.
I've done a lot of reading on different plans, and I guess what I do is called "Intuitive Eating" -- which is eating when I'm physically hungry, and stop eating when I'm not hungry. I've read "The Overfed Head" and "Intuitive Eating" and there's a thread "Intuitive Eating" (or IE).
I know other people will say "if I ate that many carbohydrates I'd gain weight" - but I'm not on a low-carbohydrate plan.
You have to chose what type of "program" or "plan" will best suit you - it might be Weight Watchers, it might be Atkins, it might be South Beach, etc. Whatever you chose, I wish you the best of luck. Keep Reading and Learning!!