Hi,
I had a demon sight period for a while (once flashes of hallucinations walking on the street, people having bizarre demon-like faces) and once for a longer time when social perception presented itself repeatedly as if people did not act as such but were expressions of C.G. Jung like archetypes (e.g. the devil speaking through the guy next table) and once sort of telepathic encounter with a demon who scared the shit out of me, I booked it under hallucination and it did not reappear. I think all this was meditation stage related and disappeared without a trace after 7 weeks of retreat (mahasi style).
i don't want to go astray if possible
I know other people with much more severe (not meditation related) special effects that usually are not in a mental hospital and when they are then for other reasons (like going violent and crazy on being 100% pissed).
It seems there is a wide range of experiences resembling even acute psychotic episodes without being such (where people still can distinguish them from "real reality"), and vast literature about it too, and we do not even have to go for the old C.G. Jung. Wilber/Engler/Brown survey the border line where meditation may become insane in "Transformations of Consciousness", Edward Podvoll comes from the other side and shows the "normal aspect" of madness (or the mad aspect of normality if you like) in "The Seduction of Madness", also in this line is "Spiritual Emergency: When Personal Transformation Becomes a Crisis" by Stanislav Grof (as editor). From these you get access to far more literature.
Seeing all this I'd rather lean back in your case and watch the scary movie, chance is not so big to go nuts as long as you keep some "basic doubt", sort of healthy general scepticism towards the "reality factor" of your experience (at least that's what Podvoll says).
You could stock some sedatives if you think that you might need a emergency break at some point.
Good luck!