I'm in the bad mood.

我的心情坏透了。

youdao

I like to hear music so much, every time when I am in the bad mood, I will take out my MP3, listening to the music, then all my worries will be forgotten.

我很喜欢听音乐，每次当我心情不好的时候，我就会拿出我的MP3，听上音乐，然后我所有的烦恼都会抛到脑后。

youdao

Neil's colleagues said he was actually in a joking, upbeat mood in spite of the bad news.

尼尔的同事说, 尽管有这样的坏消息，他居然还有心情嬉笑、逗乐。

《柯林斯英汉双解大词典》

Concentrating debt auctions on fewer, pre-announced dates risks them falling on days when the markets are in a bad mood.

ECONOMIST: Brazil��s government debt

No wonder they're in a bad mood all the time.

WSJ: Let Them Eat Fat: In Praise of Fatty Foods

Margaret Thatcher was reportedly not pleased by Cameron's efforts to indulge the current anti-American mood in the U.K. Too bad today's leader of her party thinks focus groups and political surveys are substitutes for the principles of Thatcher, Reagan and Churchill in defending freedom.

FORBES: Fact and Comment