Longest 3 Day week...

I have been working my tush off on a school project this week...and I'm exhausted.  I spent a few hours last night on it and more time tonight during and after school.  I'm starting to see excel spreadsheets everywhere!  I can honestly say that I do not know how people sit at desks and do this stuff all day.  Just 3-4 hours of it is enough to make my head hurt, I can't imagine 8.