It is probably in the job definition of a parent to worry too much. Seriously, I always thought my parents were constantly overreacting, but now I get it. Because for the parent its also often tough to tell, and its also really easy to underestimate problems, especially when they are young. So better safe than sorry, I guess.

For example, really young children can dehydrate to the point of requiring immediate hospitalization within 24 hours, which happens quite fast when they are sick.

Source: an actual anxiety ridden parent.