Oh my goodness, I'm about to get out of an almost identical situation, except sadly for me it was over five years. I stayed because of the mission, but fearing the frequent beratement, yelling, passive aggression, and backstabbing (which alternated with periods of sickly sweetness, so I never knew if I would be facing daggers or honey) shrunk my self confidence to the size of a peanut. I also picked up bad habits that I'm terrified to take somewhere else.
I finally was able to jump on a buyout (there was actually competition to get out) and will have some severance, but I don't have a new position lined up yet. I did one job interview and nearly burst into tears when they asked why I was looking to leave what appeared to be an otherwise successful career path.
In my brief Google's for help, I came across this:
http://www.askamanager.org/2014/11/are-you-haunted-by-your-last-bad-job.html
I'll be reading this thread with interest for other tips and commiseration. So sorry to everyone who has gone through this.