Sometimes kids are unhappy. And sometimes this is extremely uncomfortable for parents. In order to help our child feel better (and thus help ourselves feel better) we spring into FIX IT MODE. We bend over backwards looking for solutions, we work longer hours to afford greater luxuries, we schedule more more more to help our kids be happy.
It's exhausting. AND it doesn't work. The whole spectrum of emotions occurs despite the best circumstances.
Instead of killing ourselves controlling circumstances we'd be better off putting our energy into supporting the upset. In the face of empathy a human being is actually incapable of holding onto an emotion. Rub their backs, nod understandingly, mirror the emotion you see and slowly but surely it will lift (away from BOTH of you).