I feel awful.

我觉得难受极了。

I just feel lousy.

我心里难受。

I feel oppressed by the heat.

我感到闷热难受。

His separation from his friends made him very sad.

他和朋友分别使他十分难受。

His letter left me feeling pretty bad.

他的信使我感到相当难受。

Too much drink makes him feel ill.

喝酒太多使他感到难受。

My cough is rather troublesome today.

我今天咳嗽得很难受.

I had an especially rough time during my first semester.

我第一个学期的日子难受极了。

Even now when I think about it I feel pain in my heart.

就是现在想起来我心里都感到难受。