Either of these is correct.
Boy: I haven't left the house all week, I've been on Tumblr all week and have only moved to pee, sleep and eat, what is life?!
Can also be used when you are speechless and there are no words to describe your thoughts.
Friend 2:.......WHAT IS LIFE?!?!?!
Boy: Someone robbed my house then set it on fire......
WHAT IS LIFE?.