lose it v.
1. [1950s+] to lose control temporarily; in an extreme case to have an actual mental breakdown, to go mad.
2. [1970s] to lose one’s virginity.
3. [1980s+] (US campus) to be surprised, to be shocked.
4. [1980s+] (US campus) to vomit.
5. [1990s+] to lose one’s skills, abilities.
6. to pass out.