I tried to quit my first job twice and they convinced me both times to stay even when I knew I was underpaid and doing more than people earning more than what I did, after I managed to negotiate a nice but not amazing salary I was fired by the boss's niece because she didn't like it that people believed in me more that they believed in her. Best thing to happen to me ever, not only they paid me severance but I found a job with the same salary and less obligations right away which made me look up about how much should I be getting paid. Fast forward 8 months later I was getting almost twice the amount they were paying me at my first job.
I know it's scary to be jobless but sometimes you have to look for yourself how much you work is valued instead of believing what some assholes in some companies tell you, they will undervalue your work and convince you they are doing you a favor just by letting you work there.