overreact
v. B2 Upper Intermediate US //ˈoʊvɝɹiˈækt// UK //ˌəʊvəɹɪˈækt// over·re·act
v. to respond to a situation in a way that is much too strong or emotional. You do this when a small problem makes you feel or act like it is a huge crisis.
v. to respond to a stimulus or situation with an intensity or emotion that is disproportionate to the actual circumstances. Often implies an unnecessary or excessive reaction to a minor event.
Don't overreact to the small mistake.
He tends to overreact to every little criticism, even when the feedback is meant to be constructive.
While the initial data suggested a significant downturn, the board was accused of overreacting by halting all new investments before a full analysis of the market was complete.
From over- + react.