Stressed out:

壓力過大

例句：

When we're tired or stressed out, home is always a shelter for us to have a rest. 

當(dāng)我們疲憊不堪或者壓力過大的時(shí)候，家永遠(yuǎn)是我們休息的庇護(hù)所。

Under the gun:

壓力大

例句：

I'm really under the gun today. 

我今天的壓力真大。

Relieve stress:

減輕壓力

例句： 

Massage is used to relax muscles, relieve stress and improve the circulation. 

按摩可用于放松肌肉、減輕壓力和促進(jìn)血液循環(huán)。