My anhedonia was one of the first symptoms of Major Depression that I developed. It happened very gradually, but it was one of the first things that happened in a long, upsetting chain of events.
I am happy to report that it is reversible. I am an artist and a designer, and the thought of these things leaving me forever was very, very troubling to me. Things got so bad at one time, that simply picking up a pencil with an eye towards doing some sketches, made me tremble and become very panicked.
But with time, and tenacity (pushing myself to gradually bring art, and music, back into my life (at the edges, and only what I could handle), I have gotten approx. 50-75% of my joy in former pleasures back.
I credit the combination of medication and stubborn (but gentle) exposure to these things with helping me heal.
This is not a small thing---although the outside world will probably never, ever grasp what it is like for those of us who suffer through this.
Many hugs.....

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Do what you can, when you can...and be gentle with yourself.