Yuki couldn't sleep all night, not because she was sad, nor because she was having a lot of problems that made her stay up all night in a very horrible way. This is something that has never been imagined, in every way and process everything will still be fine in every way possible. Yuki himself feels that she is the stupidest person in the whole world, how could he not, this is still about Yuki's conversation with Kenzi and until now Yuki still remembers that Yuki can't sleep because of it.
Yuki's chest beats erratically, Yuki's heart feels like it's about to burst, and Yuki's stomach is filled with fluttering butterflies, everything feels so very real and convincing.