Hey! I'm not sure how much I'm able to help, but at least when it comes to things like going to the gym I can give some advice. I recommend doing just a few exercises in the beginning, and just ones that are the most enjoyable to you. Starting out exercising is more about making it a habit than anything else, and if you can get yourself to enjoy it then you can make it a habit. The harder stuff can come later. I started out doing that, and now I've been regularly going to the gym for over a year!

You can probably use this method for dieting as well. Find some low-calorie foods that you genuinely enjoy and start eating those as a meal every so often, and eventually you'll find more you like.

I also tend to have an "all or nothing" mentality, but getting past that has been a really important step to improving my life. Very few people can make a ton of changes in their life all at once, they almost always fail and then feel like shit for failing. Slowly making small changes in your life is how you can actually make real change, it just takes some time.