Supply really may be an option for you. I left my school utterly demoralized and felt useless and that there was no way I was going to be able to continue. I signed up to 6 local agencies and for the first term, I think there were only 2 days where I wanted to work that I wasn't able to because no one phoned me. Yes, some days I worked as a cover supervisor or a TA or a HLTA, but I always worked. Several schools began to ask for me by name and I became known as a specialist in a couple of primary schools (I am secondary trained) which opened doors I hadn't previously considered (about half of my job is now working with nursery, EYFS and KS1). The agencies appreciated my flexibility and a couple of them phone me every year to check if I'm back on the market! After that, I started on longer term contracts for a couple of years till I got my current job where I just stayed. The school paid a fee to the agency that had supplied me, no questions asked, because they wanted me to stay.
What supply did was give me breathing space. It also taught me - very quickly - that I was capable of teaching anything and everything with the minimum of planning put in front of me. Really helped with the thinking on my feet skills and whilst I had always worked in challenging schools and was no stranger to having to manage behaviour, it massively honed my behaviour management skills. I am a far better teacher today than I was without that supply experience.
I would urge you to speak with supply agencies now and sign up for them - it can take up to 6 weeks to get a DBS through and several weeks to manage the registration process (although you will have to provide references from your current workplace so I guess you need to be clear on whether you're staying or going). You will need to put a DBS on the update service to avoid having to pay for separate checks with every agency. Don't do what many supply teachers do and stick with one agency because they're all chasing the same work and the work within a given area is limited. Schools change their allegiance to an agency at whim. Signing to several agencies mean you are seeing all the work, not just some of it. They soon get to know who can do the job and will pay a premimum for you to work for them - and for longer term roles, you can play them off one against the other for the higher daily rates. It's a game but once you learn how to play it, supply can really work for you.
Anyway, take care of yourself and don't let them get to you. It's a sign of the times that experienced teachers are being subjected to this kind of treatment.