I am dejected by sobering lessons and have no need for medicine; this weakness of mine is born of grief, I am not physically sick.

The poet gently turns away those offering medicine, explaining that his pale, frail state isn't caused by any physical ailment. Rather, it is the quiet exhaustion that comes from witnessing the harsh, sobering truths of the world and carrying the heavy burden of heartbreak. When the soul itself is drained by sorrow and disillusionment, no physician's remedy can ever cure it.