Sorrow a Sin?

I found myself reflecting on the Seven Virtues and how they relate to the Seven Cardinal Sins. While reading I came across this tidbit…
“When Thomas Aquinas described acedia in his interpretation of the list, he described it as an uneasiness of the mind, being a progenitor for lesser sins such as restlessness and instability. Dante refined this definition further, describing acedia as the failure to love God with all one's heart, all one's mind and all one's soul; to him it was the middle sin, the only one characterized by an absence or insufficiency of love.
Despair describes a feeling of dissatisfaction or discontent, which causes unhappiness with one's current situation. Since unhappiness inherently results from the sin, the sin was sometimes referred to as sadness.”
I understand how sadness can interfere with one’s ability to connect with God in prayer, but is it really a sin? In my own experience sadness has brought me closer to God, that in those moments of lowliness, God is able to show himself to me. If someone were lost in the pits of despair, is it really their fault and can they just decide to not be sad anymore? The condition of a person’s soul is complex and being human, the hurtful things that we experience may take a while to heal. Someone who has experienced an unfortunate tragedy who finds themselves lost in grief and becomes depressed, is it a sin or is it an opportunity to invite God in? We should never have too much of one thing in our lives, and maybe the point that Thomas Aquinas was getting at is to not let sadness take over our lives. I believe we need sorrow in our lives to make us appreciate the joyful moments. Sorrow can be a blessing, not a sin. If life was full of happiness, why would we want to leave our earthly home for our eternal home? We need sorrow in order to draw ourselves into the arms of God.