We often feel from doing anything when we are not at our best health-wise and emotion-wise.

discouraged 意為『感到氣餒、失去動力的』。雖然 discourage sb. from doing sth. 是常見動詞句型，但在本題中，feel discouraged 描述主詞的身心狀態；這種『氣餒無力』的狀態導致主詞不想做任何事（from doing anything 在此表行為的阻礙或結果，而非 discouraged 的直接介系詞搭配）。相較於其他選項，discouraged 最能體現因身心不佳而缺乏動力的語意。