Such dream is very common among children, and among adults is usually accompanied with anguish, denoting to fear of falling into a catastrophic situation. Once we are awake, it could be good to analyze, to investigate the basis on which our actions are settled, from the moral, economic, sentimental, etc., point of view. It may be that the dream is telling us about the fear of giving what we considering as lower instincts. If we dream that we fall into an abyss but we managed to get out of it, or we are forced to cross it on a weak walkway, it means that there is a possibility to recompose the situation and regain happiness, but all this after great efforts. If we see the abyss but we did not fall in it, it means that we still feel we are in time to avoid the evils that threatening us.
Read more about dreaming of Abyss in other dream meanings interpretations.