Lose it [luːz it] [лу:з іт] — психологічно зламатися під тиском проблем, не контролювати свої емоції, "псіханути".
My boss yelled at me yesterday, and all of a sudden I lost it and cried in front of him.
My boss yelled at me yesterday, and all of a sudden I lost it and cried in front of him.