Am I experiencing paranormal activity?

I asked this yesterday, but I've added more. So yesterday, I was home alone and I was in one of our bedrooms looking for something, when I heard eerie singing. It sounded like children, like something you hear in a creepy ghost film. It was so clear, as if it were coming from inside the room. But it wasn't, so I checked the next room, but the very second I stepped into the other room, it stopped. Like I said, I was home alone and no tv was on. Then later that day, my brother and I were outside and heard what sounded like a little girl giving a short scream with no girl in any neighboring yards. And since yesterday, our dogs keep barking toward the back room, where I heard the singing, with no apparent reason, which they never do.