I have to say that I totally understand your post and sympathise. It's not you, it's the terrible education system that we have all allowed to happen. Schools are perfect breeding grounds for bullies. The pressures, the pressure-cooker, the stress, the politics, the frustrations, the lack of time for friends and family. People go into survival mode, they do whatever is necessary to protect their job, even if it means stabbing people in the back, and looking good to their superiors so that their job is safe. Survival of the fittest. People search out the weakest, to make themselves look stronger. I have seen it many times. It is like this in many schools nowadays.
Strange (and disgusting!) isn't it that teachers stand in their classrooms teaching children not to bully, SLT preach new PSHE guidelines, tell us about protecting children from harm and then they bully, bully, bully. Such hypocrites, but again just following the system, and protecting their jobs.
Get as much sick pay as you can firstly. Resign, to leave at the end of it all. Then do what I did and do supply. I supply a couple of days a week on my own terms in a school that treats me well, not because they are lovely (I am too old in the tooth to think that, such a shame I know!), but because they need those days covered and they know I could leave at any time. I do a decent enough job, so for this reason, they don't harrass me or upset me, as I am in control, knowing I can walk out with a day's notice.
Whilst all the contracted teachers are attending staff meetings, stressed out, doing IEP's, displays, ringing parents and taking work home, I leave at 4pm, as "I'm supply on a daily rate of pay that isn't to scale". I work day to day on a few of the other days, if and when I want to. You don't have to suffer in this ridiculously stressful situation. Turn the tables and do supply. It's so much better and amazing how attitudes change when they need me and I don't need them!
It's not you. Forget it, see them for the bad bullying leaders they are, and get out. I have been in similar situations. Don't give it any more thought. Look after yourself and as I said turn the tables!