I'm all at sea.
我是一片茫然。

I'm throwing in the towel.
我认输了。

My heart is heavy./I'm heavy-hearted.
我心情很沉重。

My heart is heavy./I'm heavy-hearted.
我心情很沉重。

It's hopeless.
没希望了。

It's the end of the world for me.
对我来说这简直是世界末日。

No such luck!
没那么好运气！

I'm downhearted.
我感到灰心丧气。

I don't feel like doing anything.
我提不起精神做任何事。

I'm on my last legs.
我真是山穷水尽了。