Yeah it's just as tough when you're the subject of someone's affections and you're the one not returning it.

It's kinda freaky and a little worrying when someone obsesses over you (it's only happened to me once, mind).

I think that if you've told her that you don't feel the same way, you've done the right thing in setting her straight. But ultimately it's now her responsibility to get over you and move on. Clinging onto an unrequited love is indeed unhealthy, and it's very uncomfortable knowing that someone is harming their own life over you. But so long as you've told her, there's nothing else you can really do.

I suppose this is probably why when a girl turns a guy down, she often plays match-maker between the guy and one of her friends - to get out of that situation. You don't often see guys doing that though