Its PTSD, most people who've had PCS have PTSD so your reaction is quite normal considering how PCS has impacted your life. Stress and anxiety shut your brain down, try to alleviate that and you should improve. There are ways to take a load off like meditate and give yourself time to connect with the event. The good news is the event is over and its time to process it because your stuck on it. Give yourself a day to think about the event and be with it but after that let go of the moment.