I'm mainly here to give you a big hug
I don't know much about PTSD, but take care of yourself. You are obviously a fighter, but sometimes old demons jump on us. Give yourself time to fight it properly! Self defence isn't something to feel guilty about, even if it's against memories.
It's often impossible to fight on many fronts simultaneously. You should neither tear yourself apart trying, nor tear yourself apart with self-blame. You need to be strong to be of help to others, and strong doesn't mean carrying the world on your shoulders. It means realizing when something weakens you and confronting it. Trying to just bear with it is often no better than turning your back to the problem, asking for it to break you further. I've been there, despite being through way less than you did. So you surely need to be careful.
Is it possible to get extra personell to handle more of the triggering situations? I agree to the suggestion of you handling more administrative duties. You already built an entire non-profit for your purpose, think of what you can do for it to keep being helpful even when you're not personally involved in the triggering stuff. If you find hard to trust others to do that part of the work, which I can completely understand, then you can focus working on your people skills and your management skills. You don't have to walk away, but you probably have to adjust the way you work. There are many ways to help.