Post-traumatic stress disorder.........let's drop the "disorder" for just a moment and talk post-traumatic stress.
Post meaning "after". "After Trauma and Stress".
How would you respond after experiencing trauma and stress?
When a person is in a situation of mortal danger, the fear of potential mortal danger or the position of power to inflict mortal danger, the brain has a natural defense system that kicks into gear.
This defense system knows automatically what you should do in that moment. This often means that the emotional processor is on hold. You aren't fully recognizing or processing the emotional response to what you are experiencing because you can't. The brain is in survival mode. Do what needs to be done to protect the being it is operating and think about how you feel about it later.
In my experience, this is why someone can feel that they "handled it" and are fine after trauma, but seem to develop a myriad of emotional symptoms that sneak up on them later. Often times after a period of time goes by, sometimes weeks, months, a year......it can be difficult to attribute the symptoms to an experience that seems to have happened ages ago.
Post-traumatic stress is a walk back in time where pieces are being staged for you to be able to interpret your emotional response to it. Unfortunately, it is a highly unpleasant and equally traumatizing experience as the initial event. Sometimes it can feel worse than the initial event because you are no longer in the position to "just handle it." Your brain somehow knows the difference and is forcing you to process what you now don't want to see or feel. This means you are now in a position to feel that you need to escape what you do not want to feel.