I also think you should listen to that little voice... that's screaming at you. It led you here... a place I didn't find until I was on the verge of leaving as well.
Anyway, when I felt like that - low, struggling, and questioning if I was making the right choice, I would write emails to myself. And then read them again the next day or the day after.
They were phrased from the point of view of my sister or a cousin - loving, not condescending, but allowed me to talk it out to myself.
I still look back at one in particular where I actually wrote out my boundaries. It really, really clarified things for me.
Good luck in your struggle.