I believe that the first answer, recovering from love, is correct. Because he could not recover his love, which is sometimes referred to as a fire, he is sad or in emotional pain.
Henry Fleming is a character in a book titled "The Red Badge of Courage" by Stephen Crane where he was mainly described as the main protagonist, the Youth. He started off as a young, naive soldier who wants to join the military without thinking seriously about it until his character grows into accepting his cowardice and selfishness and eventually comes out to be one of the bravest soldiers.
