I keep hearing things...

Okay so yesterday I was really tired and I was laying in my bed and as soon as I closed my eyes I heard what sounded like someone coughing. It wasn't loud but it sounded like someone from a distance but it was right in my ear. (If that makes sense.) And a couple nights ago, around 4 a.m, I heard three knocks coming from the bathroom. (Which is about 3-4 feet away from my room.) And I hear whistling sometimes. So far I've heard the whistling twice. It's really starting to scare me...