It's obvious. She's lost the person she was with, whether leaving them herself or she being the dumped party. Either way, she's worried that she might have just permanently lost the best thing that ever happened to her. She doesn't know exactly what she did wrong ("somehow i broke it"), but this is one of the final straws in the hay pile of mistakes she's made ("i only know breaking"). She knows exactly what she wants, though, and it's the person she just lost ("and what i want to lie in" - leading into lie in the sound, I'm assuming).
It's obvious. She's lost the person she was with, whether leaving them herself or she being the dumped party. Either way, she's worried that she might have just permanently lost the best thing that ever happened to her. She doesn't know exactly what she did wrong ("somehow i broke it"), but this is one of the final straws in the hay pile of mistakes she's made ("i only know breaking"). She knows exactly what she wants, though, and it's the person she just lost ("and what i want to lie in" - leading into lie in the sound, I'm assuming).