I've fallen behind too with my online ranking, but this is mainly because I play most of my games offline with the Spun Out mod enabled, or I practice in the editor with test mode. I really can't be bothered to do spinners when I'm practicing, since it's just a waste of valuable energy, and it wears my arm out.
At the beginning of July I was ranked at #157, and now I've dropped to rank #464 from not playing online much.
This isn't new. I was nearing rank 25 a few months ago, slowed down my playing, and by the time I could get back, I was already below rank 100. Some people just like playing osu! I guess.
・・・妖怪が鍛えたこの楼観剣に 斬れぬものなど、あんまり無い! The things that cannot be cut by my Roukanken, forged by youkai, are next to none!