I don't think this is a "suck it up" thing. No one deserves to suffer like that day in and day out.
There is definitely a problem here but it may or may not be the job necessarily. Being a band director is absolutely a stressful job for many, but it sounds like it's impacting you to a whole other level.

If you switch careers, there is always the possibility that this might follow you to whatever new career you choose. I strongly recommend you see a therapist before committing to any sort of career change. I don't think anyone on the internet is going to be qualified enough to guide you through this because it sounds like there may be a bigger underlying issue here.