how do you deal with bad chess days?
Like the song lyric goes...
Sometimes youre the windshield, sometimes youre the bug.
That's the truth. I bled about 150 points yesterday because I got frustrated and kept playing until 3 AM.
When I have a bad chess day, I've learned to walk away from the 'puter. I've lost 200 rating points in tactics in a matter of hours. One of my worst games -- blundering away a queen on move five -- was while trying to play through a migraine headache. I've noticed my abilities wax and wane. I don't play as well if I have not gotten enough sleep or I'm stressed out about work. I've noticed I play better after a couple cups of coffee. You could try putting out some unrated challenges if you feel you're having a bad day, even challenges focusing on a particular opening. Working tactics generally tells me if it's going to be a good or bad day.
I don't expect to reach master status, at least not until I reach my 70's in a few years ( : so if I'm having a down day due to blunders, being unable to find good plans, missing tactics, etc. I just chalk it up to a learning experience. Even if I'm not learning anything, I assume that somewhere deep in my brain, I've learned something that may tie in with something else!
Recently, I've been trying to be more aggressive in my play and am whacking lower-rated players but, too-often, launching attacks without adequate preparation against higher-rated players that they refute.
There have been days where I've seen nothing but disintegrations of my positions but that's ok, at some point in the future I'll find a better mixture of attack plus overprotection.