Oof. Yeah. I’m so sorry! It’s hard enough to grieve and start moving on when you have to see your ex regularly, but to have to stick it out living together a few more weeks until you can move out must be really difficult.
But I agree with others that it’s great that you did what was right for you, even though it’s painful. Several years ago, after ending an LTR, I cried to an older coworker about how much it hurt and sucked, and how it felt abrupt. And she told me that it was actually a good thing. I was able to recognize, relatively fast, that something not-fixable wasn’t working for me, and I didn’t try to force something that wasn’t trying to force something that wasn’t working anymore. Same wisdom applies here, I think!
Anyway, take good care of yourself! I hope you are meeting fun, new people through school who can help keep your mind off things.