A Dance with Darkness by Jenna Wolfhart

I’ve always felt like an outsider. Until my eighteenth birthday, I didn’t know how true that was. First, I started seeing strange things. Then, the tips of my ears began to shift. Now, even touching something made of iron makes me sick.
Am I losing my mind?
When four mysterious fae males corner me in the street, they bring terrifying news: I’m not human. I’m a changeling, a fae swapped at birth.
Under their powerful yet infuriating guidance, I return to Otherworld to train at their academy and determine to which of the four faerie courts I belong. But there’s something much more dangerous than the four fae vying for my attention.

And if I don’t unravel the fae’s secrets, none of the changelings will survive. Including me.