I'm an activist also. I know what it's like to be deeply committed to a cause/issue, and I certainly understand being actively involved in an issue that is not exactly "safe" as well. I don't have PTSD from my activism, but I have suffered other adverse mental health effects... I'm schizophrenic, and I have to be so careful that the natural paranoia I feel being involved in this stuff doesn't turn into full blown psychosis.

I had to take time off for several years because my mind snapped from the stress of it, and I fell into a psychotic episode that resulted in a huge personal mess. I'm glad this happened in a way though. Why? Because now I know my limits. I know now when I need to take some sort of break, back off a bit, and so on.

Really, as a general rule, for me personally if I've gotten to the point of feeling constantly paranoid, exhausted, and unable to have a "normal" conversation... odds are it's time for me to step back.

I've also had to prioritize, because as you said so well I only have so much strength/energy. I had to stop throwing myself at every single thing that's wrong and desperately needs fixing. I am only one person, and really, for me accepting that I'm only one person helped ease some of the pressure I've felt in the past.