Using 前 and 後 with Time versus Duration

Question

I have the following 2 sentences to translate for class.

Sentence 1:

頭痛がするので、
四時前に
帰らせていただけますか。

Sentence 2:

四日後のしけんは、
むずかしいかわからないので、
自信が持てなくて、 心配だ。

I think these mean the following.

Sentence 1

I have a headache so
before 4 o'clock
can I go home? (can I receive your action of letting me return home)

Sentence 2

As for the ... test,
I didn't know whether it would be difficult so
I could not have confidence and
I was worried.

I have the following questions.

1. Is my translation of sentence 1 correct? Specifically the "before 4 o'clock" part.
2. Would the 四時前 be said as よじまえ?
3. Is my translation of sentence 2 correct (what I have). And how is the missing part translated? (test after the 4th day, 4th, etc)
4. How would the 四日後 be said? よっかご? よっかあと?

Answer 1

1. I believe there's nothing wrong with your translation for the first sentence.

2. Yes.

3. As for the test (I'm having) in/after four days, I don't know whether or not it will be difficult, so I don't have confidence (I am not confident/ I have no confidence), and I am worried.

4. よっかご

The translations for both sentences could of-course be better phrased to sound more natural in English but may be you were asked to do a more literal translation?