[PoppyBlue]

The thing with dreams is that sometimes how you feel has more weight then what actually happened. Based on the actions of the dream you shared I would say that you are 1) very protective of your book and 2) might be a little worried about losing your control over things (the messy room). So I see fear and control.

The teenage girl could be just a messenger. Perhaps a man will be coming into your life in some capacity and she's just letting you know.
Her amusement could also be a message for you to relax a little and not worry so much. You were frantic and she was still and smiling.
Again, how you felt when you saw her could indicate something else about the teenage girls presence so I am only going off based on your physical description of the dream.
As far as all the people in your living room, I get nothing. Perhaps a gathering at a time you feel is not ideal.

Your Question: If you had a spiritual hijacker you would know it as a feeling of being followed or that you wern't alone. This wouldn't be a positive feeling at all. I'm not sensing that you do but if you feel otherwise, simply ask Archangel Michael to cut all negative cords from you.

your second post: You wanting to go out of body and your guides not answering...To me this sounds like your guides didn't feel it was a good time for you to be traveling. Maybe something you were going through at the time left you less than optimal at them moment. That's most likely why the 3 guardians pulled you back to yourself.

Hopefully some of this helps :)