Creative ruts can happen to anyone, not just creatives. You could be in a job for too long, where your opportunities for growth are dwindling. You could be at the top of your game as a snowboarder but can't land any new tricks... It can, and will happen to everyone at some point or another, but overcoming it can sometimes prove to be the challenge itself.
There is no single solution for breaking it up, everyone's brains work in different ways. However, there is perhaps a simple tool that can help you break it.
I was recently listening to a NPR podcast featuring legendary climber and entrepreneur, Yvon Chouinard. There were a lot of great things that Yvon spoke of, but one of the things that stood out the most is "take a step forward and see how that feels, if it feels good, take another step, if it feels bad, I step back."
& perhaps it really is that simple...
Taking a step forward, in any direction is better than being planted on your feet. In my case, I have spent the last 3 years pursuing outdoor photography. The last year I haven't been motivated, i've lost interest and now I have to take a step in a different direction. It doesn't necessarily mean that you won't end up back on that same road, but maybe you will have a different perspective.