Lyric discussion by Camikaza 

Cover art for Sleep lyrics by Poets Of The Fall

Personally....I think it's indeed about someone's past...

You're feeling the rush of anguish settling You cannot help showing them in.

To me it is as if you're waking up a day, feeling down and already feeling the depressed feelings weighing upon your shoulders, and even though you know it's bad, you can't help but to give in to them...

Hurry up then Or you'll fall behind and They will take control of you

Here it's like the singer is telling the other that if you don't 'fight' against them or something, those feelings will take control of you, resulting in a person getting depressed.

And you need to heal The hurt behind your eyes Fickle words crowding your mind

This made me think of someone with a severe inferiority complex; every time you look into the mirror, it hurts to see yourself and words like 'ugly' 'fat' or something like that pop into your mind...

....Then again, this is only my way of seeing things ^^"