Sounds like a concentration state to me. Strong concentration can do all kinds of wild things (for example, have you ever had the experience of someone else's face changing when looking at them?).
I base this on the fact that your ability to meditate returned soon after (you were probably just freaked out) and more importantly this:
Attention remained focused, and actually became more focused in that time. All peripheral awareness dropped off and there was only the image of "my" head, but it was more like I was looking at me (rather than an image of me), somewhat like autoscopy.
Attention becoming more focused and peripheral awareness dropping off sound like concentration to me.
Either way, nothing to worry about (it seems that there are all kinds of wild phenomena that are very unpleasant but basically harmless). All the best.