Maybe she doesn't do anything with her life; maybe she sleeps a lot, when she's not messaging you. She's probably enjoying the attention you give her, which isn't bad, but maybe she's growing a little obsessed about it if she in fact doesn't have anything else to occupy her mind or day-to-day life. Which is unhealthy, and seems as though you're already becoming frustrated/annoyed about it, in which case either talk to her about it or move on.

I know I'm a lot younger, but there was a point in my life where I didn't care about myself, and had no motivation or care to really do anything, but that was due to mental illness. Whether it's the same for her or not, I don't know. The only thing that I ever really did was talk to my online "friends" and it became the focal point of my every day life because I never used to do anything else.