속이 상해요 · 속이 상했어요 · 속상해요 (common one-word form)
to be upset, to feel hurt, to be distressed
Example
열심히 준비했는데 시험에 떨어져서 속이 상해요.
I prepared so hard but failed the exam, so I'm really upset.
Word parts
상 hurt
속 = one's insides; literally 'one's insides get hurt.'
Good to know
In speech it's usually one word, 속상하다: 정말 속상해 죽겠어요.