Weird dream-any interpreters?

Ok , I always have dreams that my Grandma(who died) comes to my house and acts like everything is normal. Like were having a party or something and everybody is talking to her and I always am afraid of her and scream "Your supposed to be dead!" but everyone else tells me that she's not dead and she died 7 years ago and I have had this dream a few times...anyone know what this means?