I had a guilty conscience and could not sleep.

我问心有愧，睡不着觉。

《牛津词典》

What if he got a guilty conscience and brought it back?

如果他问心有愧把它带回来呢？

《柯林斯英汉双解大词典》

So I have now a guilty conscience and a grandma's purse.

所以现在我买到的是一个难看的包包，并且还让我心里感到很内疚。

youdao

Americans, perhaps because they have a guilty conscience, think of the IRS as being omniscient.

CNN: An Overtaxed IRS

For an eater suffering from a guilty conscience, a spoonful of vitamins makes the fattening food go down.

FORBES: Fructose Nation

The plaintiffs also have to show executives acted with scienter, or guilty conscience.

FORBES: Confidential Witnesses Can't Save $100 Billion Wachovia Lawsuit