She has extreme anxiety coupled with probably being too online and such. You watch the news, you're addicted to social media and all of that and all it does is reinforce the idea that everything is shit already and going even more to hell and everything is going to kill you or cause you harm and give you terminal multiversal ass cancer. She basically needs to just disconnect. Get rid of her smart phone, don't watch TV, etc. at least for a while while having someone good, even someone like Fushimi, to talk about things with.
Also therapy isn't as much of a thing in Japan but from what I've seen it's like everywhere else where they'd probably just put her on pills and turn her into an SSRI zombie because hey, she can't be crushed by her anxiety if she's so doped up that she can't really feel anything in the first place.
you just wrote fanfic. the author has placed literally zero emphasis on this character and her relationship with the internet, yet half of your entire post is about her “being online too much.” where did this narrative come from lol?
(of course, i don’t doubt this happens in the real world; i know it does. too much of one thing [i.e., wrapping yourself up in anxiety-inducing social media] is never good, obviously… but i just wanted to point out that this has nothing to do with what happens in the chapter, and that it feels like you’re projecting or something.)
also, even if she was chronically online, simply “disconnecting” from everything isn’t gonna do much for someone like her lol. like someone else said, it’s clear to see that she most likely has something along the lines of OCD, which is a lot more complex and harder to treat than just general anxiety, imo.