*I'm playing devil's advocate here*
If you're not on contract or anything, and you have such a horrible supervisor that is effecting your emotional and physical health, why would you even consider that everything's going to be alright soon and continue doing something that's obviously bad for you? Why the guilt?
Getting a job would be tedious but doable since you already have a degree; what other people think don't matter (you're an adult already, why do you care what they think?); why stay in a place that is obviously toxic for your health (unless you received some payment; even that is questionable); if you are passionate about the topic, do you think working with horrible supervisors would help you with your work; etc.
I know the above is debatable; feel free to chip in.
*Again, I'm playing devil's advocate here*