Acrophobia
This may represent an actual conscious fear, or symbolise the fear of falling. That is, you can fall from grace, fall from social favour, fall in other peoples opinions. Such fear often has a base of anxiety about losing control, or having control taken away.
But something found useful in practice is to actually visualise falling. See Fall into the Big Black Hole.
Useful questions are:
Am I frightened that if I am not in control of my life things will go haywire?
In what way might I lose my balance in life?
Am I dealing with the fear of death here?
How can I change the imagery and feelings in this dream?