Just life. You know how the universe is against you sometimes. Some days being a fat old guy who is never going to get laid again, who really does not make any difference to anyone in the world, just sort of gets me down.
I would just stay in bed and die if it were possible. But alas, it doesn't seem to be possible, so I get up, and go through the motions of living another day. Sometimes it even helps. Today I went skiing, didn't fall and kill myself, got some sun and feel a bit better tonight. Hence you are getting a reply.
Take it easy.