I _believe_ I had the same anesthesia done when I went in for an endoscopy procedure roughly a year or so back. Supposedly the doctor had told me how often to take the prescription, I had sent iMessages/SMS' to people as well. Later that day I had nearly no recollection of any of it.

It's a very odd feeling for sure. Nothing serious and I doubt it caused any damage, but it was the first time I'd ever just had a blank set of time that I just couldn't answer for. I did have family nearby though.