He was pulling himself up and fell. He started to cry but then did a scary arching back, breath holding thing. Then went limp and starey eyed for a fraction of a second, then started to cry again.
It was scary until I remembered that dd used to do the same. He was fine shortly afterwards, crawling around and playing. I was a bit shaky though!
Anyone else's children do this? Dd hasn't done it for so long I had almost forgotten.