Well this looks familiar. In fact I think I had the same problem, but (thankfully) with fever losses.
I've been grinding NL5 for 2 weeks or so, and had a nice winrate so I decided to try NL10. Lost 10 BI in 3 days, all in equity says I should have lost 1 BI. And although I could blame it all on badbeats and setups I think that's not the case.
Why I realized was that moving up the limits I tried to adjust my game too much instead of just playing like I played NL5. I had this attitude that said players at NL5 are better so I have to play better and I have to keep working on my game and evolve all the time. In reality though, I should have just been playing the way I was always playing.
The trap goes like this. You come to NL10, and naturally you're scared that there are better people at the table. So you're playing a big pot against someone who looks like a good reg, and you have this feeling of my usual play won't be good enough to win here. You try to make a play and put yourself in a spot you're not very comfortable with (because in reality it's not well thought trough or familiar) so suddenly you're under a lot of pressure. There's double the money you're used to in the pot (which is a big factor), you feel like you're outmatched by a better opponent and you're doing something you're not used to doing. Now even though this may not lead to short term mistakes (but usually it does), it will take much more of your energy, making the grind a lot harder. Naturally, being used to your usual grinding routine, which does not evolve hard thinking every 10 hands, you try to compensate your losses by grinding more, and end up playing under huge pressure (because now you're trying to win money you lost back), and with less energy than usual. And this is a huge breeding ground for mistakes and tilt.
At least this is how it worked for me, and a friend who recently went to NL200 from NL50/100 had the exact same problem.
bah, wall of text
short term things that help for me are, I play 2 limits at the same time. Like I will open a NL10 and NL5 zoom table at the same time, so I can directly see what I'm trying to do different at NL10 and stop myself from doing it.
I also took a day off, had a decent night of sleep and some stress relief (sports and killing stuff in videogames), and now I feel much more comfortable at the tables.
anyway hope I'm onto something here and that it helps ♠_biggrin: