Something weird? I don't understand why this could even be possible. Hearing something that isn't there?

A few years ago when I was in middle school still, during summer vacation. I slept on my sofa almost every night. One night I laid down on my sofa and about thirty minutes later I heard a voice of a man, it sounded like a man speaking into a walky talky. And it sounded loud and clear as if he were standing in the same room as me (or the walky talky was in the same room as me i suppose). I was laying silently on the sofa and i heard the man's voice out of no where he counted down very seriously and slowly " 7... 6... 5... 4... 3... 2... 1... 0..." I froze with fear when I heard the number one. I laid as still as possible completely terrified all the way to the number one, I cringed on the number one. After he paused after zero I sat up from the sofa and I heard the counting AGAIN I started bawling, I walked around my house in tears turning the lights on around every which corner. I started crying "stop please stop" I think at one point I even yelled at the voice "STOP!" it counted down from seven exactly three full times until I reached my parents room crying. "mom, where is it coming from?" "where is what coming from" "the counting!" my dad yelled at me to go to bed... I haven't really heard anything like that before then or after then either. I would occasionally hear laughing but I didn't think much of it considering it felt or sounded friendly. I've always heard faint conversations but I was always positive they were subconscious or "just in my head." But I'm not entirely ruling out that the voice I heard wasn't imaginary, I'm am just looking for a better explanation as to why in any cirstance. Opinions? Comments? Has anyone else experienced this? Could it maybe be stress?