After years of wondering about tone-deafness, I seem to be getting the opportunity to learn firsthand. I don't particularly need sympathy or advice..just thought I'd post in case anyone besides me is vaguely interested in the subject.

My process:

It's going in slices.
First, I had a surgery that left me with an exhausted, inconsistent voice that was a lot of work to use. I had no volume, but on good days, I could hear pitch well enough to change keys and do a very little bit of singing. It would have been awful to hear, but the surgery was to fix my arms and I was using guitar for rehab.

Recently, I found that I can not anticipate chords anymore.
When I sing, I can tell that I'm Far Off..but can't figure out how to change my voice to match what I am aiming for..can't really tell WHAT I'm aiming for.
Apparently, my ears are very closely hooked to my voice as far as music goes. I was surprised (horrified!) about that.

I don't like the way music sounds anymore.
It sounds like noise. The way I hear harmonies and instruments working together has changed.

You know how you run a melody through your head..sometimes just because it's nice and sometimes because of earworms?
I can't do that.

You know how one song hits a trigger in your ear/mind and reminds you of another..so that if you sit around singing, you can just go and go and go because music just sort of links to itself if you let it?
That's gone.

I pick up an instrument intending to play whatever I've thought of (since it's rehab, I'm sticking to stuff I know easily) ..and the melody isn't in my head anymore.

I grew up in a musical family.
This is the first time music has been hard for me and I certainly didn't expect my ears to follow my voice downhill.

Weird.
I feel like Algernon.