1) Black dog 2) Blues 3) Despair 4) Despondence 5) Disconsolateness 6) Dumps 7) Gloom 8) Grief 9) Heartsickness 10) Misery 11) Sadness 12) Sorrow 13) Unhappiness 14) Woe 15) Wretchedness 1) Dejectedness 2) Dejection 3) Depression 4) Despondence 5) Disconsolateness 6) Heartsickness 7) State of being despondent 
• (n.) The state of desponding; loss of hope and cessation of effort; discouragement; depression or dejection of the mind.
De·spond'en·cy noun The state of desponding; loss of hope and cessation of effort; discouragement; depression or dejection of the mind. « The unhappy prince seemed, during some days, to be sunk in despondency .» Macaulay. 
[n] - feeling downcast and disheartened and hopeless
despondence noun feeling downcast and disheartened and hopeless
state of being despondent; depression of spirits from loss of courage or hope; dejection.