Just remember that babies' heads are hard enough to withstand the knocks and soft enough to not break - my DS, if he wants more sympathy because he went down on his bum from walking, rolls onto his side and looks at me THEN hits his head on the floor! He also bashes it on the side of his cot at night - oddly enough, for comfort. He headbutts doorframes and the bath too - if there was ever going to be a baby with concussion, it would be DS (we have oak floor, tiles and marble floor in our house). He's absolutley fine - well, as fine as you can be being brought up by me!

He's probably crying more from shock/tiredness than pain, a bump that would have me howling DS can ignore, but if he's tired just sitting down on a well-padded bum on a carpet is a time of misery.