First, I never under-bid on a contract, except once in exchange for equity that seems to be panning out. Know your value and values. Stick to them.
When I quit full-time employment at a major US university, my first contracts brought in far more than I had been earning. A former colleague there used to quip, "half a day's work for half a day's pay". Still, I had about six months of mortgage payments and other living expenses saved before I took the (abrupt) leap.
I took some part time gigs minding friends' art galleries to cover groceries and to get me out of the house. I've added side-hustles as a way to improve my communication skills and get me into other communities.
When I quit, I made the transition from project management to software engineering. I taught myself python and javascript. I learned how to do stuff with Django. I contributed to open-source projects, first improving documentation, then code. Those activities increased my sense of self-worth and reduced stress.
And I cut way back on expenses. I eliminated dining out and drinking. One of the perks of my side hustle is deep discounts on clothing and gear required for the job.
To manage the stress, I started hiking every day. (Actually, that wasn't the reason, but a side effect. The reason was to help a roommate lose 50 pounds, then the next roommate another 50 pounds. Bringing in roommates also offset some of the costs of living.) Removing four hours of daily commute let me hike an hour a day and still have three bonus hours that I could devote to other stress-relieving strategies such as reading or meditating.
Financial stress is just stress, as far as I'm concerned. I had one major financial obligation, a mortgage three years old at the time right as the financial crisis hit in 2008. If things had gotten very bad, I probably would have short-sold my house, moved in with friends or family, and/or found a lower-cost community to call home. And nothing but stubbornness and a desire to work on my terms prevented me from seeking regular employment.
If I had a partner and/or kids, the calculus would have been different. Another breadwinner would have smoothed the finances. Kids might have prevented a move entirely, though I'm not certain. My dad lost his engineering job when I was seven. He took on contracting work until one of the contractees hired him as SVP of engineering.
An ex just visited for a month with her boyfriend. He lost his job as an EMT in Alaska because of structural changes in state employment. We spent a lot of time talking about what we really need to survive. He says they can live happily in Anchorage on about 18k/year. (Health insurance there for them costs 1/10 of what it costs where I am.)
Just because you have financial security at your current gig today doesn't mean next month's check is going to clear. The boss works for you, you don't work for the boss.