If you’re tired, just keep working and don’t stop until you’re done. Otherwise, you’ll never get it done.
Don’t get distracted by your FB/Twitter feeds, phone calls, blogs, news, etc. Focus on what you’re doing and just push through the fatigue. You’ll be exhausted by the end, but you’ll cross the finish line. If you stop for a break before then, it’s over.
Breaks can come later. Doing is now.