I hate everyone except for the girl I like who's been in a mental hospital for over a month now with no contact with the outside world
What is it about this girl in the mental hospital that you like so much?
Her smile is great, and she makes me happy every time I'm with her.
Hating everyone can be satisfying if you've been treated poorly by people, but overall it is more unhealthy than anything else. Love everyone for who they are.
I don't want to leave her. It would feel like I'm betraying her.
No one is saying that you have to leave this girl. It's just not healthy to obsess about her to the point where you hate being around anyone else. Make room for everyone in your heart.