I've heard 'artist' applied to a musician who's playing the same piece of music that a hundred thousand other mucisian's have played. So, the music isn't original, but how it's played may be, so the interpretation and spirit placed into the piece has to count for something.
So, ask yourself these:
"Do I care?" - most true artists rarely cared what anyone else thought of their work, they did it for themselves. Der Kapitan points out that a great kit can be 'destroyed' but what if the creator thinks they did an original interpretation of the kit and they view it as art? Is it?
"Do I have to show it?" - Public review of an artists work is generally something most artists dread and usually do to pay the bills to make more art. Are you in it for the sake of it, for the glory or for the money? None are bad, but most artists have something inside them driving them to do 'art'. Good or bad is subjective.
"How do I take negative criticism?" - Fold up tent and go home? Try to please the critics? Give the critics the big middle finger and get the next thing in your head out onto your chosen media? If it's the latter, you probably have the heart of an artist. If either of the former, you probably aren't.
There are numerous examples of artists old and new that break the concepts I'm getting at so even that is impossible to appropriately define. Art, to me, by definition is impossible to define. It's just something we know when we see or experience.
You know when you're an artist when you suffer like one...