Does anyone else had a problem with acting out their daydreams?

Lately I've been doing it in public and it's beginning to cause people to ask me "what's wrong?" after I've stopped acting it out.

It's very embarassing. I'll suddenly go into this very vivid daydream and then begin running (it triggers an urge within me to run) or i'll start gesturing and making faces and then a few seconds later realize i'm doing it. And the person who is with me will be giving me the oddest look and then it makes me feel very awkward indeed.

I know I'm not psychotic. I know what is my daydream and what's reality.
It's like i black out and go into a different world entirely for a few moments and then "come to". very odd. This has been going on for a few years now.

And it's very embarassing when it happens when i'm around someone else. :l

Does anyone have any insight to add on this? Anyone else do this?