How the fudge am I going to focus,when I'm seriously stressed,frustrated and depressed because of what I've done?
I'm always at the state of anger,hate and sadness on myself.

You seem to be worrying too much about getting things done, which is causing this problem. The idea as a whole is rather daunting, but must be broken down into pieces to make it less so. Hating and hurting yourself isn't going to yield any desirable effects, but just make a big mess and only make you want to forget about it all and give up.