Keith has had a bad day at work, and he is feeling old.

基思今天工作不顺利，而且他觉得自己老了。

youdao

Feeling old and blue? Green tea may help.

感觉衰老和忧郁？和绿茶可以缓解症状。

youdao

He could not help feeling a grudging admiration for the old lady.

他不禁感到不得不钦佩这位老太太。

《牛津词典》

There is this feeling in the song "I Ride an Old Paint."

VOA: special.2010.03.25

The old man was not feeling very well.

VOA: special.2009.12.26

Eighteen-year-old Placida knows that feeling.

VOA: special.2010.05.13

Wearied of politics, feeling old, he retired at the end of his second.

WHITEHOUSE: George Washington

People say they get tired of feeling old.

WSJ: Not Content to Sit on Porch, Florida Retirees Rock On

Physicians are changing, and I have a feeling the old guard in place today will be gone in a decade or two.

FORBES: Dinosaur Doctors And The Death Of Paternalistic Medicine