The striker has joined Sheffield Wednesday on a three-year deal - just 12 months after his £400,000 move south from Aberdeen.
And after making only three starts for the Rams before being shipped out to Portsmouth on loan, he admits he could not wait to leave.
He said: "I wasn't given a fair chance. I scored two goals in three starts and there wasn't much more I could have done.
"I ended up playing in the reserves and training with kids. I don't know what went wrong there. I asked Clough if there was a problem and I don't think he liked that.
"I'm happy to be out of there after the way I was treated."