Clockwork Angel, by Cassandra Clare

“Sometimes,” Jem said, “our lives can change so fast that the change outpaces our minds and hearts. It’s those times, I think, when our lives have altered but we still long for the time before everything was altered—that is when we feel the greatest pain. I can tell you, though, from experience, you grow accustomed to it. You learn to live your new life, and you can’t imagine, or even really remember, how things were before.”