I wouldn't say she hates herself. She's just down in the dumps since she has dedicated her life (probably) to military arts after she ran away from what you COULD call a "set for life" scenario with her rich family and all, and she can't get up there with Layfon (Who has been hesitant for a while now, and even though he has all that power wants to be the opposite of what she is striving for, which in turn has her
...) even though she's trying her hardest.
Then again we don't know what she was going through living "luxuriously" so that's just an assumption at best. Maybe we'll get more on that later. Some of her motivation is due to her attachment to the Zuellini fairy or fairies in general which we know a little more about at this time.
The defense of the city and the recent platoon match were a great wake up call for her, which in turn made her up her training up a notch to the point where it could be life threatening.
She wants to be up there so bad, but she's impatient. Granted, the filth monsters aren't going to wait around until she reaches new heights to attack so I guess the sense of urgency is understandable.