Kim Ha-na no longer sleeps or eats and is haunted by the voice of her 17-year-old brother, calling frantically to tell her the ferry he was aboard with more than 300 classmates and staff from his high school on the outskirts of Seoul was sinking.
More than 50 people are now known to have died and 252, mostly children, presumed dead in the upturned hull of the stricken vessel that capsized off the southwestern tip of the Korean Peninsula on Wednesday.
Since then, Kim and hundreds of other relatives have spent 24 hours a day waiting helplessly for news in makeshift accommodation at a gymnasium in the port city of Jindo, the center of the rescue operation.
They live and grieve together, packed into the floor space on narrow, thin mattresses, taking to a communal microphone to vent their hopes and their anger at government officials over the seemingly slow pace of the rescue and patchy information.
Kim's brother, Dong-hyup, was one of 339 pupils and teachers from Danwon High School on an annual outing to the subtropical island of Jeju, making up most of the 476 passengers and crew.
"He called me at 8 a.m., saying the ship is sinking. Then I lost him," Kim, a 22-year-old student, told Reuters.
The Sewol ferry took more than two hours to sink in calm waters on a well-traveled 400 km (300-mile) route from the mainland South Korean port of Incheon to Jeju, a journey of 13-and-a-half hours.
The gym has become a focal point for anger and fading hope.
It was also the scene of one more tragic death. Kang Min-gyu, 52, the Vice Principal of Danwon High School, went missing on Thursday and was later found hanged with his belt from a pine tree outside the gymnasium.