Yes, it is not just the "incident" but also how is "triggers a PTSD episode" as well.
Yes, it "is" hard and even harder when other people don't understand the challenge of it.

However Rose, if you have others that "do" understand the challenge and you get a chance to "work through it" you will "gain". Some "triggers" are harder than others are. You have actually been doing that all along and have been "gaining" Rose. It is important to remember that and be "patient with yourself", because it can be easy to slide into the "doom and gloom". It doesn't have to be that way either, if you get the right support and give yourself some time, you will get back to making "gains" again.
It is not set in stone when you are challenged, the more you realize that the more you will continue to gain.

You are going to be ok, just be patient and whatever you need, just come and talk.

(((Hugs)))
Open Eyes