lose your head

lose (one's) head

To lose one's composure and act emotionally or irrationally. You need to calm down before you talk to Larry. You don't want to lose your head before finding out his side of the story. I'm sorry, I lost my head out there. There's no excuse for what I said.
See also: head, lose

lose your head

COMMON If you lose your head, you panic and do not remain calm in a difficult situation. He warned the party not to lose its head, saying that it was not a `time for panic'. When he was questioned by the police, he completely lost his head, told a number of lies and forgot to mention one or two things that might have helped him. Compare with keep your head.
See also: head, lose

lose your ˈhead

(informal) become unable to act in a calm or sensible way: It’s a very frightening situation, but we mustn’t lose our heads. OPPOSITE: keep a level head
See also: head, lose