I was in a situation quite similar to this a couple of months or so ago.
My advice would be to cut her out your life completely, at least until you stop wanting to be with her. I know you've said that you're not too amenable to this suggestion, but what have you got to lose? In your own words, seeing her makes you 'extremely depressed', so what are you gaining from remaining friends? Possibly you still quite like her as a person, and that's understandable. But you each want something radically different from the relationship, and I don't think a healthy, equitable friendship can be maintained in that sort of situation.
You're right in saying that you might not get over this until you find someone else to direct your attentions towards. And that almost certainly WILL happen , no matter what it seems like right now. There have been a few times when I've had thoughts along the lines of 'nope, no-one will ever match her'. But I've always been proven wrong. It's pretty much necessarily an over-reaction because, i) everyone has flaws and ii) there are lots of people out there, some of whom are really, really ace.
So, yeah, my advice is to avoid doing anything that makes you think about her. Slowly, you'll get over it. All in time. And when you've done that, she'll still be there, quite possibly ready to resume a far less draining, difficult sort of friendship.