@HornI forgot which is it. I'm sorry.
It was in early chapter long time ago, when Takae wants to make a move in front of Ushigome.
Horn replied that it was chapter 67. I re-read it and it looks more to me that Ushigome seems to have lost all hope, which does fit her personality. She does everything full throttle, putting her whole heart into whatever she is doing. Most of the time that leads to her being energetic and positive. However, when something negative happens it leads to her being very depressed. At least that is what it seems like to me.