First off, I *Love* this song! Craig projects such emotion that I can't help but get a little weepy when I listen to it.
My personal opinion regarding the lyrics is that he's talking about his own misgivings and insecurities regarding his/the band's success. I think he's speaking of his fear that he won't live up to the expectations of the fans. Maybe I'm just getting this impression because of last summer's failed (thank god) suicide attempt, but that's what I take away from this song - that he's afraid he isn't good enough.
Again - my opinion. You provide your own salt.