Actually, I am one of those lucky souls who is 
treated for an otherwise debilitating case of 
clinical depression, so I can really identify 
with how you're feeling.  I've lost track of how 
many times I've gone through that same place, 
wondering why I'm so tired, lackluster, and 
whether anything will ever turn on the "happy" 
button again.  The past year or so I've been 
having a happy little midlife crisis -- nothing 
like being almost 45 to make you wonder what 
you've got to show for that much time and 
effort.  (An aside: one of the things I enjoy so 
much about the anime/cel hobby is that people are 
generally so very accepting...doesn't matter if 
you're 12 or 65, fat or ugly or drop-dead 
gorgeous).

But you know, it always ALWAYS works itself out. 
As others have said, make sure you're taking care 
of your physical body.  Stretch, exercise, enjoy 
the sun.  Think about the _good_ part of the fact 
that you're in Japan, you lucky thing, which is 
something that many of us are unlikely to ever 
have a chance to do! :)  And TAKE time to do what 
you need to do.  To hell with the rest of it; if 
you can't make yourself happy, or at least semi-
content and sane (!) then nothing else matters.

I have my gallery offline for overhaul at the 
moment so I can't show you my happy cels.  Think 
of Akari and Kris sharing a huge happy hug! :)

Feel better soon.