A song about someone you love who doesn't love you back.?

I'm in this situation right now, and I need a song I can just play and play and play. Currently I'm listening to death cab for cutie - what sarah said. But that's not even about why I'm sad :/ so are there any songs that sound like that? or sia - breathe me? cause i love that song too. I also love coldplay - fix you, and the scientist. I just want a beautiful song that is about loving someone who doesn't love you back. Or something to do with that. Thanks :)