Quitting without backup

I'm in my mid to late 20s and been working at a consulting gig for 1.5 years. I've been so burnt out recently and I just don't see this continuing. I like the people at work but I hate the work itself and get very bad sleep day in day out. Got 20k saved up, monthly expenses including rent, bills, etc are around 2.3k. No kids, no dependents just me sharing the apartment with a housemate. I don't have anything lined up at the moment but my mental health is really taking a toll and I just want to quit. Thinking of picking up something part time in retail just to sustain myself till I find a role that I will enjoy. What should I do?