I was 1540 recently in blitz and fell to less that 1200. I played at night when i was very tired. Not a good idea to do it.
I think you might have an addiction.
I think many blitz players have an addiction that is similar to a gambling addiction. They keep playing thinking their 'luck' will change.
This is why I always say you can feel happy if your rating doesn't fall after playing many games in a row.
I feel a little happy when my rating doesn't go up. There is too much pressure to maintain.
Btw, I "fluctuate" even in a single game.