Heck no you're not over-reacting. I worked in a toxic work environment that I was determined to stay at because I wasn't a quitter. Big mistake. After 6 years I had a nervous breakdown and ended up leaving. In my case it greatly exacerbated my bp2 and anxiety. Be gentle with yourself and start looking for other things to do. Life is too short. It's great you have a supportive fiancé. Good luck and best wishes.