What does "heaviness" mean in the lyrics below by Adele?
When will I see you again?
You left with no goodbye, not a single word was said
No final kiss to seal any sins
I had no idea of the state we were in.
I know I have a fickle heart and a bitterness
And a wandering eye, and a heaviness in my head
But don't you remember, don't you remember?
The reason you loved me before,
Baby please remember me once more.