After defeating the vampires, everyone was able to come back from the other side, except for Damon and Bonnie. They were stuck there. Everyone thought they were dead and there was no way they could be brought back. But in reality, they went back in time to May 10, 1994 and have been reliving that day ever since they got there.
You and the rest of you split up after that happened. Stefan left to start a new life, Caroline is always on the outskirts of Mystic Falls with her mom, and Jeremy and Matt are in Mystic Falls. You were in college (you were Damon's girlfriend. His first real girlfriend). You couldn't handle the pain of losing Damon, so you had Alaric erase all the good things about Damon, now you think he's a serial killer. You're also a vampire. You're in a hospital now, on an internship, where you got pretty close to a boy.
One day, Damon suddenly returned, by chance. Bonnie sacrificed her way out and herself for Damon so he could return to you. Bonnie stayed with Kai on the other side. Damon immediately rushed to you because he missed you so much. But he didn't know that now you thought he was a cold-hearted serial killer, because Alaric, in order to help you, erased the good parts of Damon from your memory. Alaric promised to only do it back if you asked him to, but you didn't want to. Now your life was good. Damon went to your room (he loved you very much), and you were sitting on the bed.