According the classical "Possessions for Dummies", the first steps (opression, infestation) seem to have been done by whatever it was. The next step (possession) usually is preceded by some sort of tricky invitation using the weak victim's will (the dream about the guy claiming "let me in!"), but our friend's will seems to be on guard, even asleep. Actually we don't know the OP's conscious & subconscious personality of emotional charácter, personal story from childhood and true essential psychology. She says she's narcoleptic and suffers sleep paralysis' episodes. She seems to manage some amount of periodical stress by whatever. Maybe she is simply the focus of poltergeist activity being its epicenter her own psychic & emotional stress projected on her daily background under some kind of personal contexts... Go figure.