it's about experiences Jack has had in his life."froze in time between hearses and caskets" and "an eighteen year old who didn't know what loss was" refers to his sister Sarah who died about 10 years ago of cancer, and also to the fact that he witnessed 9/11 from his classroom window. "lost control when i panicked at the acid test" is about when he was 19 he took acid and he didn't come down for ages and he thought he'd ruined his life and he panicked.
it's about experiences Jack has had in his life."froze in time between hearses and caskets" and "an eighteen year old who didn't know what loss was" refers to his sister Sarah who died about 10 years ago of cancer, and also to the fact that he witnessed 9/11 from his classroom window. "lost control when i panicked at the acid test" is about when he was 19 he took acid and he didn't come down for ages and he thought he'd ruined his life and he panicked.
here's an interview where Jack talks about bleachers, and what this song means: http://news.iheart.com/articles/offbeat-468707/offbeat-with-bleachers-12228132/