Sleep can be a challenge with PTSD. When you wake up like that though it means your brain was just trying to figure out how to feel about that letter and apparently you are very unsettled about it. You are expecting something bad to happen and be caught off guard, I have bad dreams like that too. Well, that is because something bad did happen and it was traumatic and you are not sure how to settle that emotionally either, I have that challenge myself.

Finding ways to be in the "now" and be calm does help with that though. Meditation is good because you are learning to sit just in the now and in relaxation doing nothing and being "ok" with it.