Hello and welcome! I hear exactly where you are coming from!!!! EXACTLY!!!
I have and still do have an extremely hard time understanding how my last job brought me to my knees and produced my PTSD. My therapist explained that I have lived with trauma throughout my life in many forms and that the daily abusive and toxic environment at the last job were the final blows for me mentally. Don't know if it's the same for you or not in that regard, but I am continually shocked that the flashbacks, nightmares and intrusive thoughts are ALWAYS about the last job and not anything else I ever experienced in my life. I avoid all contact with those people except for those who had my back through the ridiculous situations but were powerless to help other than to comfort and listen. I can't even hear or watch the stupid commercials without being majorly set off.
My therapist said that working there was like being in the trenches of a daily war, never knowing where the next bomb would explode, who would shoot their proverbial guns at me and who I would be trying to save next. I watched daily as people broke down and I worked hard to lift their spirits. I would have meetings where people were visibly shaking, flushed faces, profusely sweating and unable to speak or form coherent sentences, and everyone was experiencing memory and word loss while those in power continually fought against each other, ripping their partners apart and then taking it out on everyone else with conflicting and impossible orders.
Even writing and recalling this is bringing emotions back and I'm shaking, but I am hoping to give you an idea that trauma can come from many places and each looks different. I would further question the person who diagnosed you about why and read up on PTSD to see if it seems to even ring true for you. For me personally, when I finally read the DSM-V and other sources, the light finally went off. "Hey, that's me nearly to a T!"
Wishing you the best in your journey, and again welcome!