1. 你看起来很不舒服,要不要去休息一下?
You look under the weather. Do you need to have a rest?
2. 我有点儿不舒服,想先回去了。
I am a little bit under the weather, and I want to go home now.
3. 在这么大的压力下,人们很容易感到身体不适:
It's easy for people to feel under the weather under so much pressure.
(在很大的压力下,under so much pressure.)