How long would you continue going to work unhappy?

My job sucks so bad. It consumes my thoughts. It's stressful, boring, the people suck.
I'm applying elsewhere but I'm quitting before the year is up, whether i have a job lined up or not.

If all else fails, I will dumb down my resume and work at the damn grocery store or something.
I've always wanted to work at one anyway, like when I was younger. I like seeing neat shelves with everything pulled to the front and in their place