@JGoldman10,
I would if I wanted to. If the drawing was in some way unique or the smiley face was a really funny parody of the original, yes, I would try to protect it.
Stop shouting.
I put a lot of photos on line and I reserve the rights to them both in their original form and in the form they become once I re-edit them.
This is simple
and , as JoefromChicago already told you, you do
not have to register your drawing in order to copyright it.
(Did you read his link to the Copyright Office? I hope so. It's very revealing.)
Joe(Do what you think is best for you)Nation