I remember being diagnosed with hepatitis C. I never had a bad day with it, there were no symptoms, and I hadn't been doing any of the things that most people associate with it. I doubted my diagnosis but there was no way around a positive test, I had it. Only then did I do the research and find the history that made it believable, in fact, I found there were several ways I might have been exposed. I had to own it, it was mine. It didn't help that I also had to explain it to people that, like me, assumed you got it through a very few routes like needle use and homosexuality. I now knew that it could be passed through blood transfusions prior to 83, or through my work as a first responder, or by something as simple as having a roommate use my razor or being scratched by the same jagged edge as a person that had it. In fact, the first people that presented symptoms were war heroes that had received plasma on a battlefield. I did the old interferon cocktail cure for 6 months and it is gone.
My point is this: Everyone around us assumes that you get PTSD through being shot or shot at and by seeing death up close. We learn that there are more ways to get it and we have to train people, even ourselves, that there are many many ways to get this.
As long as I have had this diagnosis, and firmly as I believe I am a sufferer, if I was put in a room full of combat vets, I would feel like I didn't belong. They might feel the same way because I got here by a different route. The same goes in reverse. If I was in a room full of CPTSD sufferers, even though I was aware that there was a huge variation in the way we had all gotten there I would feel like I belonged. And a combat vet might feel like she or he didn't.
If only there was a beyond doubt binary yes-no test like my hep C tests for this, we could all get a membership card and never feel like it didn't belong to us. Instead, we have to accept it as an opinion of someone that has seen it before and learn all we can about it, and accept that there will always be a lingering whisper of the unknown and unprovable that seems to get us all at some point.
I don't think that doubting our diagnosis makes us anything but human. I trust my psych, I know why and how I got it, and I accept that others got it another way that is no more or less validating than my own. I don't worry about the first glancing blow thoughts that I don't really have it, because I know that a longer look has shown me time and time again that I belong here, I have it.