Bad days at poker affect on your state hard if you are deep in poker for a long period of time. For me, when I fall in maybe 2-3 tournaments having almost nuts and afterwards lose with some 1 or 2 outs, then I shut down my computer first step.
Go outside maybe for a fishing or riding bike for about 20-30 km easy mode with some 90 dance music, or work something else that is my hobby, even do some DIY.
I find DIY a lot helping for my bad days, when I'm loser in something convert that into a winner in different job, where you feel good after you finish it.
Knowing that you are making something on your own, give you positive vibe, because you know that you are worth for something.