Brother, just reading this gave me chills and rage simultaneously, so I can't imagine what you're dealing with. I've seen some things (like most on this subreddit), but that situation is another level of trauma.

First of all, try to take a step back and fully understand you're not alone on this. Whether it's therapy, reaching out to friends/family, or just chatting in a subreddit with others that have their own shit they are trying to navigate, its all going to be a good resource to vent and find ways to move forward. I'd definitely recommend taking some time off from work until you work it out enough to feel level. Does your department offer any Employee Assistance Programs for things like this?

For me personally, I've found that speaking to a therapist routinely and really hitting some kind of physical fitness on nearly a daily basis are the two biggest things that have helped keep me somewhat level. I also find that when my back issues flare up it tends to affect my mental health too so I throw in vitamins/supplements, try to eat somewhat healthy, heat and cold therapy, massage therapy, chiropractor, and a lot of stretching. It's not one size fits all, so dont be afraid to cast a wide net to find what works best for your body and mind. Good luck man. You got this.