Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Sadness in a dream indicates joy and happiness in wakefulness. It is one of the opposites in interpretation. Whoever sees himself sad, God will relieve his worry.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Sadness indicates committing a sin that causes worry. Whoever sees himself sad will soon be happy.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Sadness is interpreted as joy. Whoever sees himself consoling a sad person will receive a great reward.