I've had it,是一個非常地道的口語，如果你直譯成「我已經有了它」，那就很尷尬啦~
我們來看一下柯林斯詞典的解釋：
If you say that you have had it, you mean that you are very tired of something or very annoyed about it, and do not want to continue doing it or it to continue happening.
這個表達的意思是，你已經厭倦了某事，或者對它表示非常生氣，不想再繼續下去了。
I've had it = I've had enough，類似於漢語裡的「我受夠了」
我們來看兩個例句體會一下吧：
I've had it. Let's call it a day.
我實在受不了了，咱們收工吧。
I can’t believe he’s done it again. I』ve had enough of him!
沒想到他又這樣做了，我受夠了！
在美劇《破產姐妹》S04E20裡，Max和Caroline總是不好好工作，而且還經常取笑老闆，於是Han就發飆了：
That's it! I've had it with you two and your non-work ethic.
夠了，我受夠你倆以及你們的懶鬼態度！
好啦，今天一共學習了兩個表達：
I've had it (with)
I've had enough (of)
你都記住了嗎？