As the grief process shamelessly forces you on, you reach a point of desperately needing to find something to do, to take your mind away from the pain, if only for a moment. But at the same time, you don’t want to not think of her for fear that you are losing her.
In the early days after your child dies, it can be quite clear to the outside world what stage of grief you are in - shock, anger, etc. But as times passes, they see us functioning again, maybe even having a laugh. Do they think we're "over it"? We learn to hide our grief behind a mask.