耿耿于怀

耿耿於懷
gěnggěngyúhuái
to take troubles to heart (idiom); brooding

CEDICT

to brood on; to not forget about a matter and always be troubled or vexed by it

Wiktionary

有心事牵绊，不能开怀的样子。宋．文天祥〈贺前人正〉：「某迹縻俗驾，心遶贺星，遥指于轸中，拳拳公寿，雪立残于门外，耿耿于怀。」也作「耿耿于心」。

重編國語辭典

有事牵绊，不能开怀

維基詞典

Entry Composition

1 耿耿 gěnggěng
  1. bright
  2. devoted
  3. having sth on one's mind
  4. troubled
=2 于 yú
  1. to go
  2. to take
  3. sentence-final interrogative particle
  4. variant of 于 yú
=2 于 yú
  1. (of time or place) in; at; on
  2. (indicating any indirect relation) to; toward; vis-à-vis; with regard to; for
  3. (indicating a source) from; out of
  4. (used in comparison) than
  5. (used in the passive voice) by
3 怀 huái
  1. bosom
  2. heart
  3. mind
  4. to think of
  5. to harbor in one's mind
  6. to conceive (a child)