Lak has a negative vibe and it is generally related to feeling sad and depressed. It is used in particular sentence structures which one should fully grasp before using the word.
I am in a lak (aka. "tu lakam" in Farsi).
- Why don't you listen to this song?
+ It has lak ("lak dare").
- Amoo is very sad. What happened to him?
+ He did not bring his umbrella with him. He is going through a severe lak ("rafte tu lak").