How do I stop hallucinating?

I keep hearing noises that are not there, and see things that are not there. I'm not a schizophrenic. But I took this drug and idk what it is but I h8 it! ( not from a doc) I'm scared put of my mind right now and need ways of cooling down. Also I can stop thinking about random things... Like 30 minutes ago I thought about the sound a seal makes and that didn't stop until a few minutes ago... Plz help I can stand it.