Quitting job before having something lined up? Too risky, or worth it?

My current job is so awful, my mental heath is being impacted. I sit in a conference room now as I can hardly breathe and my stomach is in knots. I so badly want to put my laptop on the front desk and leave. The problem is, I don’t have something lined up. I have a few promising interviews later this week, but that’s all.

Has anyone quit without notice or having something lined up before? It’s obviously a risk, but I’m wondering if there have been wins as I’m sure I can find something in the meantime (bartender, etc)