Like I said, many are unexplainable,

that is, they can't tell if there's anything wrong, but something is apparently wrong.

Depending on how old you are, you can keep trying yourself. Then your mental state is the #1 problem. Keep banging your head against a closing door (aka job market) is pretty dumb don't you think? As a PhD you can't find an equally satisfying way, if not a better way, to live your life than to find a job most likely you wouldn't even like?