Teenage depression is impossible to take seriously. You're living in a free country, receiving a mandatory education, have a roof over your head, etc. If you really feel that bad for yourself with such a privileged life then go to therapy or have a doctor prescribe you medication for your depression.
And don't let the fact that you'll never make a difference in the world bring you down. Carl Sagan's "Pale Blue Dot" explains that. Instead of moping around feeling sorry for yourself because no one will remember you in a century, live life to the fullest.
And stop listening to The Wall, it's stereotyped as a super depressing album. If it depresses you, don't listen to it. It isn't about you, it's semi-fictional, and it's only depressing if you want it to be. Why not listen to Floyd's happier albums? Piper, Meddle, Momentary Lapse, and Division Bell all have super cheery songs on them.
