It could be any of the above you mentioned in your post, yeah. It's hard to tell. It could be resentment, it could be annoyance, it could be depression, self doubt, jealousy, etc.could be jealousy. Orihara sacrificed probably quite a lot of free time and "youth" to get where she is.
Seriously, 774 is blue balling us hard.The author's been dragging this out for so long already. Come on!