Thorne left Pride Park in January to sign a deal with Oxford, which runs until the end of the season.
The midfielder, 27, is playing for free at Oxford, according to Sky Sports, and feels he needed to change clubs to kickstart his career.
"It was key for me to start enjoying football again," Thorne told Sky Sports.
He added: “The last few years, because I haven't been playing football and other things were going on, I wasn't enjoying going into work at Derby and enjoying myself. I was going in and training with the kids.
"The most difficult thing is not being injured and still not being able to play.
The biggest thing for me was to come somewhere with someone I trust, someone that trusts me, would allow me the opportunity to prove my ability and my fitness."
Thorne continued: "I want to just find the love for it again, get myself playing.
“I'm a free agent in the summer and I've only just turned 27 so I still see myself having another good six or seven years (of playing)."