be in a mood 心情不好，在生气 （常常是生闷气）
feel blue 心情不好 （忧郁）
upset 情绪低落的，失望的
depress 比upset 问题更严重一点，由此可能会演变成depression哦，忧郁症
disappointed 失望的，这个也算是不高兴啦~~:P
down 在英文的口语里面解释成心情不好, 心情低落, 或是觉得很失望
let sb. down其实也是失望的，让某人失望了
frustrated 沮丧的，失败的，失意的
annoyed，烦躁的
lost temper 发脾气
angry 生气（比较气愤了）
_____我____是____________________分割线______________________
以下是我在天涯问答上看到的，真不好意思要copy一下， 不过我觉得写得蛮好的，以俚语居多：
心情不好
be in a bad skin
be in bad temper
be in a bad mood
be in the right vein
be out of sorts
be under the weather
be in a black mood
be in ill humor
feel nohow
out of fix[美俚] (钟表等)不准; (身体)不舒服; 心情不好
Get up from the wrong side of the bed
以下是例句与用法:
自早晨起来便心情不好
get up on the wrong side of the bed
我心情不好
I am in a bad mood.
她在心情不好的时候写诙谐的歌曲。
She writes humorous songs when she is in the right vein
今天上午老师心情不好
The teacher is out of sorts this morning.
我注意到你心情不好。
I notice that you're out of sorts
他心情不好。
He's in one of his moods.
我知道你现在的心情不好。
I know it's a bad time for you
要小心，今天经理的心情不好。
Take care! The boss is in a bad mood today.
那场争论使她的心情不好。
The arguement darkened her mood.
这些傻女人的嘲弄使我心情不好。
The Banter of these silly women has put me in a Black mood
她心情不好
She's under the weather.
我父亲心情不好,不要激怒他
"My father isn't in a good mood, don't get his shirt off."
我心情不好是因为昨天晚上睡得太少。
I am in a Bad mood because I didn't get very much sleep last night.
王小姐自早晨起来就心情不好,因此不想上班
Miss Wang got up on the wrong side of the bed and wouldn't go to work.
http://wenda.tianya.cn/wenda/thread?tid=0badfbdcd2342822参考资料：http://wenda.tianya.cn/wenda/thread?tid=0badfbdcd2342822