In general, song lyrics are subject to limitless interpretation, which is not the point of this forum. Falling away can have a number of meanings, all of which have to do with diminishing or
moving from an original position. Without specific context, it is just a guessing game, and with lyrics or poetry, even context may leave a lot of room for interpretation.
Korn is an American band that sing modern heavy-metal songs.
Puma - I'm not really familiar with the song, but I looked up the lyrics, and I would say that, here, they mean that their life is "falling away" from them. In other words, they are getting fed up with their current life, and they don't understand why certain things are happening to them. Does that make sense? Even if it does, this could be totally wrong! As was suggested, sometimes what people think about song lyrics is not at all what the intention was! But, here, it seems to be correct.