To "lose it" in English means lose one's temper. In Hebrew we say "labed (to lose) eshtonot".
Although most Israelis have lost their eshtonot at one time or another, do they know what the literal meaning of eshtonot is? The word appears just once in the entire Bible: "Put not your trust in the great, in mortal man who cannot save. His breath departs; he returns to dust; on that day his eshtonot are lost" (Psalms 146:3-4). In contrast to humanity's impermanence, God "keeps faith forever" (146: 5).
Most commentators (Rashi, Ibn Ezra for example) define eshtonot as thoughts.
In his description of the reception of prophecy, Maimonides describes a complete physical collapse and a frenzy of one's eshtonot "And the mind remains free to understand the vision". How can a frenzy of one's eshtonot clear the way for prophecy? Maimonides is consciously using this rare word with its biblical context in mind. The Psalmist mourns the loss on death of our eshtonot, which are part of our identity. A prophet must shed these eshtonot to be "free to understand the vision".
But, in this post-prophecy age, keeping our eshtonot - our focus - is the best way to face any adversity.