Mental distress
sorrow, sadness, regret, melancholy, vexation, mourning, misery, trouble, anguish, bereavement, painful regret, distress over loss, depression, despondency, pain, worry, harassment, anxiety, woe, heartache, repining, lamentation, dole, dolor, malaise, disquiet, discomfort, smart, mortification, affliction, gloom, unhappiness, wretchedness, infelicity, desolation, despair, agony, torture, purgatory.
Antonyms happiness*, exhilaration, pleasure.