You look tired. What happened?

你看起来有些累。怎么了?

I just don't feel myself today.

我现在情绪低落。

重点讲解:

I'm unhappy.

I just don't feel myself today.

表达自己“情绪低落”时，如果只用unhappy “不高兴的”这个词，则无法表达出那种“不在状态、低落”的感觉。老外在遇到这种情况时，常说I just don't feel myself today.其中 feel oneself的意思就是“感觉很好。