自分のことのように
Meanings
1
as if it were one's own affair; as if it were about oneself
Used when someone empathizes deeply or gets involved in another's matter as if it were their own. Often followed by verbs like 喜ぶ, 悲しむ, 心配する, 怒る.
He rejoiced at his friend's success as if it were his own.
She worried about my failure as if it were her own.