I think it would be pretty absurd to end on a tragedy in a manga with as cutesy and soft of a title as "My Cute Little Kitten". So I'm guessing it's all psychological and temporary they just need to finally properly talk
I mean, yeah, but what makes this frustrating is that the characters are being recklessly obtuse. When somebody passes out in the bath, that's not a little issue with her sleep cycle. That's an immediate medical concern, and the fact that mangaka seems unaware of that is very concerning.