You're Damon's girlfriend and you moved away from Mystic Falls 3 years ago. You're a human and Damon's a vampire. Damon's been vampire sience 1864 and you know it. While you were gone Damon lost his humanity to Sybil. He became evil and he killed hundreds of people. He doesn't feel anything, he doesn't care. You heard about this from Caroline and Stefan. When you heard this, you decided to come back to Mystic Falls