I would not jump directly to a diagnosis of Schizophrenia.

Sometimes people who are under stress can "see things out of the corner of their eye" or even report hearing things that are not there.

Sometimes these things can be related to fear as well. I have a fear of bugs, specifically being in my home. When I see them (in my home ) I get jumpy and it might feel like a bug is crawling on my skin.

I know this is not the case but it happens nonetheless. It's prompted by my phobia of bugs and expectation of the worst rather than a prodromonal indicator of Schizophrenia. (I hope.)