losing interest and motivation to do things that used to be enjoyable. withdrawing socially and not wanting to see people. difficulty concentrating on schoolwork, leading to falling grades. tiredness, aches and pains. changes in sleeping pattern (difficulty sleeping or sleeping more than usual). changes in appetite and weight (feeling more hungry or less hungry). feeling useless, worthless and unloved. black, pessimistic thoughts about the future. thoughts of death and acts of self-harm.