I agree that the song is a metaphor, only using the fly as a representation of the way he perceived his life at that time. "What can you do but go on?" is the defining line of the song showing that although everything is "smearing out of control" and is in a frantic state, all you can do is go on.
It also is has very visual lyrics where hallucinogens could have either played a part in the lyrical writing or as a background to the initial "out of control life" meaning where the fly is seen by someone potentially trapped in their head while tripping.
I agree that the song is a metaphor, only using the fly as a representation of the way he perceived his life at that time. "What can you do but go on?" is the defining line of the song showing that although everything is "smearing out of control" and is in a frantic state, all you can do is go on.
It also is has very visual lyrics where hallucinogens could have either played a part in the lyrical writing or as a background to the initial "out of control life" meaning where the fly is seen by someone potentially trapped in their head while tripping.
Just the way I see it ^^ -geekstyle-