when you feel upset or when you feel frustrated that something is not going the way that you wish it would.

当你觉得很失落，或者当你因为事情不像你期望的那样进展而感到沮丧时，你也可以使用这个句型。

I'm frustrated 课堂 - SpeakingMax英语口语达人

But you probably should use often because hey, who doesn't get frustrated?

但你也许该多多运用它，因为毕竟，谁不会感到沮丧呢？

I'm frustrated 课堂 - SpeakingMax英语口语达人

I was so frustrated.

我感到很沮丧。

I get so upset 实战 - SpeakingMax英语口语达人