Don't forget that there will always be flat places on the learning curve. I'm not so sure that those flat spots are not where real learning is taking place and the results then show the upward movement on the curve.
By the way, this year marks my 47th year of continuous budo training, so I have some experience to draw from. A couple of my "flat spots" have taken a few years to pass. Don't give up!
Practice for the sake of the practice and forget about getting better. It'll happen, but never the way we want it.