What does the expression “yourself not yours” mean?
Are you uneasy, has something deprived you of your mental balance? Then, you are “сам не свой” (“sam ne svoy” or “yourself not yours”)!
This expression appeared in Russian literature in the 18th-19th centuries. It was used to describe the state when a hero experienced some kind of excitement or shock, due to which they could not come to their senses.
For example, in Leo Tolstoy’s novel ‘Anna Karenina’, the main character loses her composure after seeing Vronsky fall from his horse. “As they left the gazebo, Alexei Alexandrovich, as always, spoke to those he met and Anna, as always, had to answer and speak; but she was not herself and, as if in a dream, walked arm in arm with her husband.”
An English equivalent would be: “To be beside oneself.”