What the hell was this noise?

Okay so i was having a bath with the front door unlocked (brother is out late tonight) and it was about 2:25 am. I have been hearing creaks and such all night but didn't care. So i was bathing and all of a sudden i hear a noise. It sounded like someone repeating a moan kind of sounds like "OWEA." i was shocked at first, then i thought oh its my brother playing a joke, then remembered that he wouldn't want to wake anyone. So i called out my siblings name. The "OWEA" stopped. I sat silent for about 15 minutes kind of worried. I started to not care, then i start hearing what seemed like foot steps and they were getting close to the door. So then i freaked out, and started calling for my sleeping father. He woke up and said nobody is there. Only other incident was about a year ago, nobody was home but my parents. They were both upstairs going to bed. I then heard a scraping on my wall/door. I called out every ones name and no answer. I worked up the courage to open the door. Nobody.. Whats wrong with me!? Im freaking 16 years old and still get scared!