"我心情不好"的英文怎么写,I am really bummed可以这样写吗

可以这样写.或写成I feel bad 或I am in bad mood. 也可以的

I am bored.
I am in bad mood.

心情不好 [简明汉英词典]
in a bad skin
in bad mood
in bad temper

I am not in a good mood.
I feel bad

I am in blue mood.
It's my blue day.
It's a blue day to me .

I am greyish blue.
I am DOWN.