Inner Monologue Meeting?

When you're in a quiet place, have you ever thought to yourself or had a conversation inside your head? Is this story an extension of that, or something directly inside the brain!? One night, I suddenly woke up and groggily sat up. It's still dark, so I should go back to sleep. I wonder if I can fall asleep again now, I was thinking casually. "Let's play." A voice higher than my own, like a young girl's, seemed to echo in my head. No, it's too dark now. "You're my big sister, right? Let's play, come on." I can't go, because I'm not your big sister. I have to sleep again, so bye-bye. I continued the conversation in my head without question. "Hmph." After that, the girl's voice disappeared. With a sigh, a sudden sense of fear washed over me. It was as if I had been numb to fear until now. What was that!? I panicked a little. I wondered if the nuance of "come on" really meant "let's go," and a chill ran down my spine. For now, I decided to be thankful that I was able to calmly refuse.