You're clearly very sincere and regretful... it seems quite obvious that you didn't set out with the intention of hurting her, nor did you think you were doing anything she'd disapprove of. Any girl worth her salt should be able to see that. Keep talking to her... don't give up just yet. She's undoubtedly embarrassed and hurt, but she will realize that she's overreacting. It might take time--after all, who wants to admit that they've made such a blunder?--but she'll come around. Make it clear that you're there if and when she wants to come back (and that that's what you want, too), and then give it some time.
In the meanwhile, try to be there for her the way you say she's been there for you. You say she's put in a lot of effort in your condo? Take the same kind of care with the place she's in now. Is her faucet leaking? Does she need help assembling a new set of shelves? Ask her if there's anything you can do to help her out, not because you prefer her living there, but because you still care about her no matter where she lives. Let her know through your actions that you're willing to really work for her well-being (and, by extension, the well-being of your relationship). Do your best to continue to be a friend to her, just as she has been to you.
We women have a bad habit of overreacting, especially in situations involving the folks we care about most. It's hard not to take any percieved betrayal of trust to heart, even when it's something small, when you really care about someone. But it's also hard NOT to forgive someone who really wants and deserves it. And you, my friend, clearly deserve her forgiveness; if she can't see that eventually, then you were too good for her anyway. But trust me, that won't be a problem.
- Response by southernbelle08
, A Sweet Sarah, Female, 18-21, Student