From Longman Dictionary of Contemporary Englishlose your headlose your headto become unable to behave calmly or sensibly You’ve all heard that Nadal lost his head over a girl? → lose
Examples from the Corpus
lose your head• Actually, not all of the men had lost their heads.• He made a sort of feeble pretence of being afraid that he might lose his head.• There was always something around the corner if you didn't lose your head.• But he must not lose his head and try to make up the distance all at once.• But you lose your head in this crazy hellhole, you do, and different rules apply.• The bull market in bonds finally lost its head of steam.• Buckingham lost his head over the matter.• I must be losing my head, she thought. 