It must have been vertigo or low blood pressure. That, or the blood loss is getting to her. I was wondering if the fake illness plus the poison AND the blood loss attributed to the stumble. But honestly, this plot made my secondhand embarrassment flare up and I closed the window after seeing her...
I think it's okay that she doesn't have a 'losing weight by training' arc. It's just three chapters now, it doesn't mean she won't grow as a person later. This is just one of the areas where magic is given a growth in story, not the protagonist. It's better to think that it's the world-building...
Is "rinne" hard to translate to English? Is it like a philosophy-related kind of word? What does it mean? I didn't get the TN.
P.S.: I haven't read Naruto before. Is it good?