mood swing

Translations
перепад настроения
He experienced a mood swing after hearing the news.
Он испытал перепад настроения после того, как услышал новости.
Definitions
A mood swing is a sudden and intense change in a person's emotional state, often shifting from one mood to another, such as from happiness to sadness or irritability, without a clear reason.
Words
mood

noun
настроение
swing

noun
перепад