Play your favorite tunes in the car and sing along.

It's not a "critical listening" environment.

When you get home, play your hi fi, but listen from the kitchen while you prepare a meal that smells enticing.

Sing along some more.

Have some wine.

Then, have another glass and listen until you hear a song you really like, then stroll into the hi fi room but stand there, not in the sweet spot.

Doogie:

I often encounter similar feelings/issues with another passion of mine: research.

If I am just not into it anymore; which does happen once in awhile... and has also happened with me to my ability to appreciate MUSIC and not SOUND.... here is my very serious suggestion:

Just walk away from all things audio for x amount of days/weeks/even MONTHS.... though I would guess it would be somewhere on the magnitude of several days to a few weeks..

Again, just take a BREAK...it's totally normal... I think you're just a little burned out. and a break always helps.

After the break, of which you will just KNOW when you've had enough of a break, you just may find yourself RUNNING back to the MUSIC....and again enjoying it.

Hope my advice helps,

Ron