After you went to Labyrinth to stop Luke's army, which you did, Camp lost sight of you..

You went missing, even the gods were panicked since your dad is Hades, and if he found out who made you lose your way in that hell-forbidden place, he'd kill 'em. But one day, you made it out of there, now roaming around the random place, until a camper found you. The camper took you back to Camp Half-Blood and yelled out at the gates, "SHE'S BACK!"

Everyone was confused until the saw your half-lifeless eyes and got worried before running over to you, Percy heard the yell and sprung up. He looked at you with concern written all over his face before you collapsed onto the ground, barely breathing from everything that had happened..