oh hun.
i know its a bad feeling, but they will do this and when my dd did this we decided changing her on teh floor was the safest.
then they start climbing and its all happening again.

ok nurse time now. lol
has he thrown up?
is he able to follow a toy if you move it infront of his face?
does he still have proper balance for him?
can he walk move all his limbs?
can he feel it when you touch his legs? like does he laugh if you tickle his knees etc.
has he been drowsy?

if he hasn't thrown up and not drowsy and can do the others. just keep a close eye on him.
if he starts to get drowsy not at his usual time then take him to your gp first.

dont beat yourself up to much, you did everything humanly possible you were there.
maybe just give him lots of cuddles today