Not quite sure what happened, and looking for input-

Last night I woke up after about 6-7 hours of sleep, turned on my stomach and got ready to fall asleep again. I do a reality check-not dreaming.
I looked out my window, then looked down at my nose. As I did this a little scene from the dream I had been having before I woke up came back (My eyes are still open) and it's kinda a continuation and I have no control so it's not really a day dream.
Then I notice everything around me is black/dark so I think I've been looking in the same place for a while and things have dimmed. But when I look back to where my window is, things are still black.

My heart starts racing. It feel like if I get up out of my bed, I will be in a dream. I thought I might be having an F.A...but I was just awake, and I'm pretty sure my eyes are still open. I also hear the tune jingle bells as if someone is squeaking it on my window-which I can't see. There are silhouettes of things not like in my room.

Did I falsely fall asleep? Or is this something you can do that I accidentally did?
Especially-has it happened to anyone else.

Information muchly appreciated.