Is suddenly playing bad natural when improving?

Hello, I made a new account and having trouble with rating, on my old account I used to be able to defeat 1600s-1700s and hover around 1650 before but now it seems that I am dropping rating even though I cannot really tell what I am doing differently. I am not playing tilted, I have been getting my 8 hours of sleep, and I am not sick or feeling bad. I cannot figure out what’s happening and I am confused?

We all have good days and bad days.

It's all unexplainable from my experience. I recently thought I improved a lot and lost 160 rating in 1 week otb

I don't know how old your old account was but it's possible that, due to popularity of chess rising and resources getting more widespread, 1600 back then was weaker than 1600 now.