hallucinating bugs

today I woke up and saw bugs on the walls (all my imagination), which confused and upset me, so I went back to sleep for a few more hours, then woke up again and I stopped hallucinating

?_?

OP here, I've come to the conclusion that it's a side effect of a sleeping pill that I take. It doesn't happen when I don't take a sleeping pill, but it happens pretty often when I do.