What is the ruling on saying, "It's as if the sky fell on me" or "the sky fell" metaphorically in a state of sadness? Is this considered disbelief that expels one from the faith, or does uttering such phrases as a metaphor and simile, without intending disbelief, not expose a person to disbelief?

The phrase "as if the sky fell on me" does not constitute disbelief (kufr). A similar expression was reported from Amr ibn al-Aas, may Allah be pleased with him, at the time of his death. The questioner should turn away from the whisperings (waswas) they are experiencing. For a ruling of disbelief (kufr) to be issued against someone who utters disbelieving phrases, it is a condition that they be aware of the meaning and intend it, not be ignorant or have spoken it inadvertently.