What should I do? I'm a completely miserable loser and I can't stop sabotaging my life.
Why do you think you can't stop sabotaging your own life?
I'll consider to stop it in a situation when I finally become a happy person in a happy world
You are not a loser at all! Once you realize that and stop purposely destroying your life, you will be able to find happiness.
I just see myself as complete garbage.
You just need a better attitude and to try to take care of your well being better. You can't keep thinking of yourself in that negative way.