What is he miserable about? The Jazz outbid themselves and gave him a juicy extension that looks terrible now, even with the way it's constructed. He had no market then and he REALLY doesn't have a market now.
I guess nobody likes to play like crap. But nobody is also forcing Clarkson to go out there and act like a spastic rookie even though he's on the wrong side of 30. If he knows he's in a slump, he should get back to the basics: defend as hard as he can, try to facilitate, move the ball.
Instead, he keeps going on his kamikaze runs and throwing the ball away.