My advice, and I speak from experience, is to back off and give her space and even more so, yourself. She is not an option as a girlfriend at this time, and continuing too much interaction with her as it stands now will only further your pain. Is there a chance it can change? Sure, maybe but as it is you have to accept where it is now. Any amount of trying too hard to make the romantic feelings return will only end up in pain right now. The thing is, you haven't done anything to make those feelings go away, so to speak so there isn't much you can do to make feelings you're not responsible for diminishing, return.

Another thought about space. If indeed she cares for you and finds you attractive still... putting distance between you can only work to make her realize she has feelings for you, if she does. This is positive for two reasons. If she realizes this, she will be more sure of her relationship with you. If she does not, it can only help to get you to detach a bit over time and it will become easier for you after awhile, to accept her as just a friend and move on yourself.

Hope this helps.