From Didimos' Dream Encyclopaedia
Falling in general: not trusting one's abilities, missing safety
A recent loss (of a friend etc); unsolvable problems
Loss of trust in one's opinions and ideas, waking up from too much optimism
Falling without a real reason, of free will: distancing from reality
The dark abyss:
associated to depth (of thought), infinity; search for borders
often a warning symbol; the dreamer realizes emptiness and the unknown in himself; s/he wonders about the ending, the outcome of something risky s/he did
Positive: crossing the darkness (by flying etc) -> solving solutions
Negative: being clueless, waiting, being afraid of the dark -> hopelessness, despair
Falling into the abyss: Failing or being afraid of failing, fear of life, capitulation to fears or danger, giving up
... *doesnt believe in dreams*