I'm always going through that, and you'd be surprised how many people will describe similiar events going on in their lives. Even things that people enjoy doing, such as you working on ZT or MP, when they become like what you're feeling, they don't have the motivation to do anything at all. I can't help you because everyone will give you the same response: "Deal with it", or they offer suggestions to help but not realizing how a depressed person's mind works because they've never experienced it or never experienced it on the same level. Usually this afflicts teenagers more than anyone else, and almost everyone eventually grows out of it. You're just not fully matured yet. I'm not quite, either, but at least I'm realizing how the world works.
And stop listening to goddamn Three Day's Grace and Linkin Park and Phoenix Down. "I CANT ESCAPE THIS HELLLLL...NOESSS" "IM BRAKING DA HABIITT" and "IM READI TO BELEEF!!" does not help your situation at all.