Not getting is never good a good sign. But the assumption that you can send emails only while awake is wrong as well.
Mistake. Big mistake.
Anyway - there is rock-solid scientific evidence to suggest that sleep deprivation damages cognitive abilities and decision making.
See e.g.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2656292/
Depriving yourself of sleep is false heroism. You do not "get more done." All you're doing is increasing internal friction, decreasing personal effectiveness, and making yourself cranky and stupid.