I notice when I don't get 15 minutes or more of sun a day I get really lethargic, I'm not sure what your personal situation is, but every morning I open my shades to let in some sun and it's enough to get me moving. It doesn't make me feel better/happier/undepressed, it just shakes the cobweb/sleepy/lethargy away enough to make me a bit more functional. Have you tried something like that?