“没什么，只是心情不好而已”怎么说？

nothing,just in a bad skin !

我是这么认为的，不知道对不对。

Ls,i agree with you ~~

more:

nothing,just an ill humor~

not,but a bad temper~

Phuu~~,just a little moody~~

还真对了，呵呵，意外！~

nothing serious ,just a bad mood

Nothing serious, just a little upset.

呵呵。。。謝謝！！！

nothing, it's just I am not in that mood.

不会啊啊啊，

日常用语啊，

楼主好好学哦！

嗯嗯。。。我會好好學的。。謝謝各位

no matter,just a little unhappy.

唉，看来啊，我跟你们比，简直就是幼儿园的小朋友！！汗

instead of saying " how to say "

try to use HOW DO YOU SAY ......

you are not wrong, but they Westerners use the later one more often

Nothing serious, just a little upset.

Oh nowlt,a bit upset//Oh nowlt,not in a great mood

nothing serious, just in a bad mood.