I feel the answer to this is complex and depends on the lens or perspective you choose to view these kinds of experiences through. Psychology, religion, mysticism, science, philosophy, and supernatural schools of thought would explain these phenomena differently.

Yes, psychosis is a plausible explanation and would most likely be the go to explanation for modern day psychologists. Psychologists who are more analytically inclined might wish to explore the symbolism in it relative to your unique psyche as well as its relation to the collective subconscious.

It seems to be a pattern that these types of events take place when we are stressed. Nobody has a definitive answer as to whether this occurs because our brains are at that point more able to see and interpret a normally hidden, but naturally occuring phenomena OR if the stress on our mental state brings forward hallucinations of things that do not actually exist. At any rate, the experiences create very real feelings that we must navigate through. One's choice of explanation for the occurrence can heavily sway the way we feel about the experience.

For me, the goal is is to determine what within me triggers these types of events. What might be out of balance and what am I meant to learn. The answer to that is most definitely different for everyone. For example, one might know this sort of thing indicates the beginning of a significant downward spiral and they might seek to rebalance or to adjust their current treatment plan to accommodate. Someone else might find the experience curious and uplifting and a sign they are spiritually supported. I'm not promoting either view as it is wholly subjective. I know this answer most definitely offers nothing in terms of concrete truth, but paradoxically it is the most truthful answer I can offer.