Solitude or loneliness: the feeling of being alone or isolated, including emotional loneliness or social isolation.
都会の大勢の中で逆に孤独を感じることがある。
Sometimes you feel lonely despite being among many people in the city.
長期出張で家族と離れていると孤独を感じる。
Being away from family on a long business trip makes one feel lonely.
孤独を感じたら、無理に我慢せず誰かに相談しよう。
If you feel lonely, don't force yourself to endure it—talk to someone.