The first obvious choice is getting fit, although it's about two years I'm trying different diets with no results.

To emphasize the rational in my reply: I challenge you by saying the above claim is not true. Dieting for a day or a week or a month with no results is possible (and frustrating). Dieting for two years "with no results" means either a rare medical condition (seek help from a professional) or, more likely, you are dieting incorrectly and refraining from rationally noting this fact and trying to be less wrong. A big hint for me is you ask what exercise you should do and you do not say what you've tried. You can eat optimally and be unhealthy if you do not excercise minimally. This is not esoteric information so again I challenge you that you are self-sabotaging.

I have been where you are. Now I am healthier and happier. Having many people say 'aw, it's okay, be yourself' didn't help. A few people who spoke bluntly (far more than I have done here to you) was the trick. Letting myself off easy didn't help. Changes helped. Stopping doing what didn't work helped. Work hard to better yourself, for yourself, and many good things will follow. You will do things you don't want to do along the way, and be glad for it later.