Get Some Sleep
I am one who likes to pull "all nighters". There is something about being focused with the lack of distraction that allows me to resolve an issue or get a lot of stuff done - or so I think. On occassion, working late into the night can be productive but sleep deprivation can reduce your effectiveness short term and long term.
Your body and mind need rest. It is vital to get enough sleep. I find the quote by John Steinbeck to be true, "It is a common experience that a problem difficult at night is resolved in the morning after the committee of sleep has worked on it." Sometimes, it might just be better to go to bed, get some rest, let your mind reset and approach a problem in the morning with a fresh outlook.