That's life, man. I've been like that almost constantly since grade school. You've just got to soldier on, somehow.

There isn't a single morning that goes by where I cctually want to drag my ass out of bed and off to work, but I do it because I have to. I've got to earn money to justify living at home (because my parents sure as hell don't want to provide room and board to a freeloader), so I have no choice in the matter. If I could, I'd never leave my room.

So I guess you've just got to find a sense of duty to get through it all. Once you accept that there are things you absolutely have to do, whether you want to or not, it's easier to get through life even when you have no motivation whatsoever.