Ooh, I'm so sad.

哦，我好难过啊。

I'm so sad that I failed the exam.

我考试没及格心里真难过。

Today i'm so sad, really!

今天本人真的很伤心！

And I'm so sad that you're leaving.

你就这么走了，我真的很难过。

I'm so sad since Amy and I broke up.

自从跟amy分手后，我感到很难过。