thats absolutely awful not checking you are ok! hope you feel better soon, concussion isn't very nice!
i hope that person was just unhorsey/ very stupid and didnt realise what he was doing- however judging by the fact he didnt bother to check you hadnt cracked your skull or been kicked in the back is unbelievable... some people!
once had a young guy smugly watching his staffy bark and leap around my horses feet, the horse i was on kicked out and missed its nose by an inch. wiped the smile off his face...