You stand in the line just to hit a new low
It certainly is in a metaphorical sense, to a certain degree. Meaning that "you expect something and c get it at the end. That things don't get better for you, on the contrary it gets worse and worse. It hits a new low every time you look at the situation.
Take one down
You're taking one down
could be that the meaning is of "having a shot", drinking an alcoholic drink, perhaps to forget the bad day, or to endure the hardships of it.