Were you holding onto the phone because you were awaiting for communication from someone?
Is that why you went down stairs?? Maybe to call someone?
But you were being watched! You then went back and thought you had been abandoned. Symbolized by your losing something out of your OTHER hand.
Sounds like you are about to make an important choice that you are unsure of the outcome.
I think that you know what that decision is ... and dreaming about it this way was your subconscious mind telling you to think a little longer before making a decision.
But I know nothing... just my impression.