How to find a legitimate medium

Hello everyone. I'm trying to figure out how to find a real medium. I see many thinks online but I know there's a lot of people that are very talented in manipulation. I do believe in the afterlife however I still have doubts. Also about 20 years ago while working in a adult psychiatric hospital I was assaulted by what I believe was a troubled spirit. And yes there were witnesses. This spirit literally knocked me on my ass. Long story short ever since that night I've had extreme anxiety and depression that comes and goes. I never had this prior to that night. This hospital was definitely haunted. Even the security accidentally captured a picture of a woman while taking pictures for badges. The spirit that hit me was definitely a man and he hit me from a window (that was on the 5th floor). Yes I know it's crazy but it happened. Thank you for your help.