Paranoia Support Group
Paranoia is a disturbed thought process characterized by excessive anxiety or fear, often to the point of irrationality and delusion. It is often associated with psychotic illnesses, sometimes schizophrenia, although attenuated features may be present in other primarily non-psychotic diagnoses, such as paranoid personality disorder and obsessive compulsive disorder.
Did you ever have any dreams about this that is coming to consciousness in your mind when awake? Sounds like that shadow you saw is being blown out of proportion, have you told a doctor about this or anybody you can trust?
Hope this goes away for you
It will take time, but you can convince yourself that you will be okay. :)
Do you see a psychiatrist or psychologist?