Mark Erelli - I Thought I Heard You Knocking

I thought I heard you knocking
As I sprung up from my chair
Flung the door wide open
There was no one standing there
It's getting harder every moment
To tell what's really real
Sometimes it ain't the things you know
It's more the way you feel

I thought I heard you knocking
Tapping soft and light
Like the sounds an old house offers
When it settles for the night
You used to be just as familiar
Like whiskey on my breath
Now whenever you come calling
You scare me half to death