Am I crazy or is it something else?

Recently, as I was lying in bed, I was going through my memories in my mind and I came across this strange memory, after probing my thoughts a bit more I realized that it wasn't normal. when I was 4-7 years old and I was doing menial tasks such as brushing my teeth I would feel this strange sensation like when you have pins and needles except you can still feel and I would sort of sense this black thing creep around my vision but if I looked at it properly it would rapidly disappear. This started about the time of my friend's birthday. It continued for several years but when I was 6 I inquired of my friend who was keen in paranormal and extraterrestrial things. He told me it could be a demon or something demonic but I was skeptic.
But, after about a week I watched out of the corner of my eye and I saw something that resembled a skull. It appeared to be laughing, it scared the stuffings out of me and I never did that again.
Next year I discovered the wonderful world for science and micro-organisms and I became obsessed in making moldy bread again and again, slowly, the black thingy disappeared all together.

So, whats your opinion on this? Am I crazy? I think the black thingy stopped coming because maybe it need a believer of the paranormal to invade or something, so it stopped when I was interested in science.
anyway, just so you know, Im open to all ideas and opinions.

I would chalk it up to a vivid imagination.

Heheh, I knew someone would say that, and thats what my friend told me, but, I don't mind what you think about me... But still, what if it was real? what do you think it might be?