From what I have read and gathered, it's a 2nd concussion happening before the original one has healed it what causes most troubles. They give anywhere from 72hrs to a couple of weeks for the brain swelling to go down and heal. If you don't and they get a 2nd blow to the head when the brain is already swollen it has no room for more swelling. Then problems happen.
It sounds like you did the correct thing in seeking out trained medical professionals.