I'll typically just sit on the computer in no-man's land going GameDev->StackOverflow->Facebook->Check Email->(repeat).
Oh yeah, know that too well. Replace StackOverflow with Reddit though...
I started using trello as my todo list and it helped somewhat. Be sure to include every task that may be lurking in the dark corners of your brain.
Procrastination can be a sign of mental stress. Are you otherwise happy? I want to apologize if that question is too personal.