How do I (17/f) get my friend (17/f) to quit driving me INSANE?

Hi all. I'm using an old throwaway because I think my friend uses reddit and I don't want her to see this.

I have a friend with some issues. She has aspbergers and OCD and I think she was just diagnosed with borderline personality disorder, so I cut her super slack. But the past few months she's been really fucking clingy. She messages me EVERY DAY, no matter what the time, and usually I'm at work. She wants to hang out almost every day, and I can't really hang out except for Sundays. I've told her this, because I work a lot and I'm juggling work along with school, plus a few other responsibilities (I have quite a few pets and a pretty big plant collection). I work almost every day, after work I do schoolwork, then go to sleep. Repeat every day, every week, until I graduate. (I'm homeschooled and I'm graduating in a couple weeks).

But just receiving messages constantly, being forced to reply to them or being spammed by "hello?" "are you there?" "whateverforeverbro?" is annoying as fuck. Being asked to hang out almost every. single. day. is also annoying as fuck. I've told her so many times, as soon as I graduate I can hang out often! JUST NOT RIGHT NOW.

I'm afraid to be blunt with her, because she is pretty sensitive, and if I hurt her feelings I know she'll just push me away and never confide in me or anything ever again. I don't want that, I just want her to calm the hell down! It's like having a super clingy boyfriend! This is why I'm not dating anyone right now!! Jesus. It's getting so bad I'm actually considering cutting contact from her completely! I would if she didn't live so close, ngl.

TL;DR super clingy friend messages every day, spams me if I don't reply, asks to hang out every day. I'm juggling work and school, how do I let her down gently?