I think I would sign off, in your case. I've been as guilty as anyone in staying with a lousy job because I'm too scared to put myself out there, and risk finding something worse, but if it was bothering me the way it's been bothering you, I think I would take the leave. If my job forced me to look into medicine to help me cope, and I broke my composure and told off my evil boss, I think I would take that plunge. But I very much understand your hesitation about jumping in and doing it. It's scary!