First of all, let me assure you that your feelings are valid. Life is a jigsaw puzzle with occasional missing pieces, and in those blank spaces we have to struggle to see the complete picture if life doesn't look exactly like it was supposed to on the cover of the box.
Likewise, two people may be putting together the same puzzle, but the speed with which one is able to reach the end sometimes just has to do with the random chance in which a particular piece is added to the equation. There is no doing it wrong, and it will come together at the end.
In short, I would not say that either individual is over nor under reacting. Life changes can be a scary thing, but that means that there is growth, and growth is the most natural thing on Earth.