Elo dropped 200 points in a couple weeks
I think a couple of nights of good sleep could make all the difference.
You have played 350 5 minute blitz games in the last week. Divide 3500 by 60 to figure out how many hours that is.
I get something like 58. 58 hours.
That has to take a toll. You probably function more like a zombie.
Get some sleep.