My heart breaks for you.
I work in a hospital and see many grieving people.. And it's almost palpable - it's either the "thousand-yard stare" or complete crying, wailing distress. My heart hurts. I can only imagine the amount of healing required to get back to the person they were 1 minute before they received that phone call. That ring that changes your life forever.

Be patient with yourself and continue seeking care. It takes a lot of strength (which sometimes takes a long time to conjure) to begin healing. I wouldn't try and spend too much time on whether or not it is a post traumatic disorder. You said she died recently.. It seems too soon to add more worry to yourself over your reactions because what you went through was acutely traumatic, truly nightmarish and panic-inducing.

Hospitals are a scary place and there are good hospitals and bad hospitals, unfortunately. So your avoidance of that hospital is 100% rational in my opinion. They didn't seem to take great care of your mother, why would you want to go there? But remember.. there are good hospitals out there.