(一).I'm under a lot off pressure.我的压力很大a /我觉得负担很重。

This expresses that "I'm feeling very stressed."Usually people have this feeling when they have a lotof extra work to do.

put (a lot of) pressure on 给......施加(很多)压力

I'm under the gun.我备受压力的煎熬。

原音重现：

A: I'm under a lot of pressure at work.

我工作的压力很大。

B: Oh? Do you have to work on an important project?

哦?是吗?你在做一个重要的项目?

(二).It Couldn't have been easy. (对你而言)不是容易的事儿。

This expresses that "It must've been hard for you." The speaker thinks a person had a hardtime with something.

It hasn't been easy.不容易。

Things haven't been easy.(虽然我克服了 困难并取得了最终的胜利，但)很不容易。

原音重现：

A: How did John become so rich?

约翰是怎么变成富翁的?

B: I don't know. It couldn't have been easy though.

不知道，肯定很不容易。