>>16902431https://en.wikipedia.org/wiki/Pareidoliabasically, this says that humans are very quick to perceive patterns, even when they don't exist. and since noticing human faces would help us survive, we've evolved to pick them out very quickly, even when they're not there. there's nothing wrong here, just a weird little happening that comes from our development and many people experience it.
now, if you were to start personifying these "faces" and saying they were ghosts/demons or thinking that they were "following" you, this might be the beginning of hallucinations, delusions, psychosis. don't try to convince yourself there's anything more to this than a slightly overzealous pattern recognition algorithm in your brain.