A boy/ghost/imaginary friend named X?

at my familys old house when I was very young.. about 4-5.. I had.. a.. Friend.. named X.. but no one else could see him.. I mean i had imaginairy friends.. but i KNEW they were imaginairy friends you know? but.. X.. I dont reallly remember him at all. people claim that the house we lived in was haunted. and many think X was a ghost. but the thing was I guess he was real to me.. they'd hear me talking and having full conversations to him. But Im told that I was playing with him ALL day EVERY day. like REALLY PLAYING like a real friend. and I have a feeling he wasnt imaginairy. and im very intuitive.. i dont know.. i just want to know what you think he was? and is there any book or movie etc charectors named X?