Eenzaam gedachten.

sad
sad/
adjective
1.
feeling or showing sorrow; unhappy.
"I was sad and subdued"
synonyms:unhappy, sorrowful, dejected,depressed, downcast, miserable,down, despondent, despairing,disconsolate, desolate, wretched,glum, gloomy, doleful, dismal,melancholy, mournful, woebegone,forlorn, crestfallen, heartbroken inconsolable.