When I defended my thesis, I wasn't completely prepared but I knew my research perfectly.  I wasn't worried despite having three days to prep and having a raging ear infection. 
I defended my thesis last year, with a raging ear infection.
user
You must have been in so much pain. How did you manage to endure it?
assistant
Lots of Advil.  Thankfully, my adviser had prepared me really well.  I wasn't even nervous.
user
It great you were confident despite your illness. It's a sign of good character.
assistant