Most musicians hit this from time to time. My prescription is CHANGE.

If you play live a lot, maybe pull back and don't gig as much. Or try to work your way into a different musical niche. I went from a country band to a heavy metal band to a punk band to a latin-jazz band, and each forced me to focus on new (or old and rusty) skills.

If you play a lot, try playing less and getting into writing. Or vice versa.

If you play the same style a lot, explore a different one, immersing yourself in it to the exclusion of other styles for a while.

If you're tired of your band, get out and work alone for a while. Or vice versa.

Sometimes it's the music itself that wears me down, but sometimes it's the music BUSINESS.

Examine what it is that's dissatisfying you, and try a 180 degree different direction.

(If you're a Seinfeld fan, remember when George decided to do the exact opposite of his initial impulses, and his quality of life skyrocketed!)

Hang in there - you're not alone. It gets better, honest.