Opposite words for contentment:
sorrow, agitation, discontentedness, woe, disturbance, depression, despondency, anger, annoyance, discontentment, anguish, unhappiness, dispiritedness, discontent, rage, exasperation, irritation, desolation, melancholy, misery, discomfort, dejection, uneasiness, aggravation, joylessness, displeasure, vexation, sadness, gloom, dissatisfaction, distress, restlessness, fury, wretchedness, upset, pique.
Usage samples:
  1. He saw an expression of surprise, of anxiety, then a smile of deep contentment.
    "The Nether World", George Gissing.
  2. She could,- she thought that she could, have watched her child's happiness with contentment had Clara married Owen Fitzgerald- Sir Owen, as he would then have been.
    "Castle Richmond", Anthony Trollope.
  3. The latter, as the hour for the entrance of Belisarius approached, prepared to don his royal garments- with great contentment, for it was the last time that he would ever wear the signs of a dignity which had brought him nothing but pain and wretchedness.
    "A Struggle for Rome, Vol. 2 (of 3)", Felix Dahn.
  4. But there was a nervousness in his contentment which told the tale to any observer who might know how to read it.
    "Can You Forgive Her?", Anthony Trollope.