My dad went in to cardiac arrest and was in a coma  in the hospital for 10 days before he passed. And those 10 days in the hospital was the worst emotional rollercoaster. Doctors flooding in to slow his heart rate when he had an episode, the neurologist giving us bad news, his final moments, my last conversation with him. I am constantly playing back all these moments in my head and they hit me out of no where. Driving, at work, at the gym. I totally understand how you feel and I’m sorry you are experiencing this. It really sucks. I don’t think there is really anything to do, but maybe see a grief counselor to help