Hearing voices in my head right before sleep?

I am a paranoid, stressed, clinically depressed 16 year old. Every night before I fall asleep, I hear voices. Mind you, these voices sound like they're speaking directly in my ear, not in my head. They aren't negative, and they have nothing to do with anything that happened to me that day, and my subconscious is usually pretty descriptive about what it's trying to sort out. There was one time where I heard a male say "dude, are you okay?" and then another time where I heard a lady that sounded like one of those announcers on the train telling you your stop, except it was complete gibberish. What's wrong with me? What should I do? It creeps me out so much that I can't sleep at all.