Something's Missing by John Mayer

I'm not alone, I wish I was
'Cause then I'd know I was down because
I couldn't find a friend around
To love me like they do right now
They do right now

I'm dizzy from the shopping mall
I searched for joy but I bought it all
It doesn't help the hunger pains
And a thirst I'd have to drown first to ever satiate

Something's missing
And I don't know how to fix it
Something's missing
And I don't know what it is
No I don't know what it is
At all

When Autumn comes, it doesn't ask
It just walks in where it left you last
You never know when it starts
Until there's fog inside the glass around your summer heart*

Something's missing
And I don't know how to fix it
Something's missing
And I don't know what it is, no I don't know what it is
At all

I can't be sure that this state of mind
Is not of my own design
I wish there was an over-the-counter test for loneliness
For loneliness like this

Something's missing
And I don't know how to fix it
Something's missing
And I don't know what it is
No I don't know what it is

Something's different
And I don't know what it is
No I don't know what it is

Friends - check
Money - check
Well-slept - check
Opposite sex - check
Guitar - check
Microphone - check
Messages waiting on me when I come home - check

How come everything I think I need
Always comes with batteries?
What do you think it means?