I had a brother once
He drowned in a bathtub
Before he'd ever learned how to talk
And I don’t know what his name was
But my mother does
I heard her say it once
Padraic my prince, I have all but died
From the sheer weight of my shame
You cried but no one came
And the water filled your tiny lungs
Appear, my dear, and cry for me
Six years ago today
That I laid you in your grave
Your sweet young skin was shining then too
So tonight to celebrate i will...
I will poison myself
Another coughing, shaking fit in a bathroom
That is spinning
And I close the door
And I rest my head on the tile floor
Sickness and sleep turning me cold
I'm still not sure
Is there some better place I could be heading towards?
Where the selfishly sick and self-absorbed...
Are welcome
I saw the future once
I was drunk in a phone booth
My eyes were wet and red
But I could not tell what was said
And through the screams of the traffic
Voices carried
Saying I'm sorry
On a day so gray it's black inside
Watching churches on TV
In a coma you don’t dream
You just hope that someone sits with you
Babies turn blue when they're ignored
Like the sky on summer days
Before you turn and walk away
It has changed you
So tonight to compensate I will...
I will poison myself
Another coughing, shaking fit in a bathroom
That is spinning
The more straight forward meaning is a metaphor for a girl breaking his heart. If that was really it, this song wouldn't be that great.
The other meaning is how minuscule things from the past can come back to haunt you. A more universal approach would be to look at it as the butterfly effect working itself internally. It's kind of like taking a step back to think of things that brought you to where you are and how the past can still come back to destroy you. But in the case of the song, it's self-induced torment. And that just says a little more about Conor's personality.