Contentment is not just a matter of good fortune or chance; it relate more to character, self control and the achievement of goals.
I can conceive of no contentment of which toil is not its' immediate parent. We need to constantly stretch our minds beyond their comfort zone at whatever age, for good mental health. If individual brains cells are not stimulated, they gradually lose their rich network of family connections and become technically termed as "depression".
Try assembling all the avenues of your contentment and make yourself self-worth and fit.