Sort of going through the same loss of interest. When I analyze it I realize that over the past year I average around 2-4 hrs a day working on my music including studio time. Burn out...time to rest and "play" for fun. I play now only when I reaaly want to, I found that I was feeling really depressed when playing classical, then I decided to change all the songs from minor to major keys, major keys are not depressing. Example a song in a minor I change to A MAJOR OR d MAJOR, NOT BY TRANSCRIBING BUT BY CHANGING THE KEY SIG, I add f# and c# to a minor song, it just sounds happier.
"when all my songs were coming from minor keys I began to miss out on the Major happiness"