Those types of hallucinations that happen while we are falling asleep or waking up are not that uncommon in the general population. David Hufford wrote a really interesting book about sleep paralysis and there was a really interesting YouTube video where he describes it. I remember him saying normally if a person would describe their experience to a psychiatrist they maybe misdiagnosed as psychotic.
I have experience both myself, and there are some similar characteristics in the hallucinations, but they are two different things.
When they do happen they can be kind of frightening but just try and think to yourself ( well that was interesting )
I think it was Emerson that said, knowledge is the antidote for fear.