I've/I'd been working late this month

[EngLearner]

Sarah has been working late almost every day this month, so she tells her boss that she needs a rest and asks him if she can go on vacation. He tells her that she can as of the next day. So the following day, Sarah stays home. When her husband returns home from work early, he notices that she's at home when she's supposed to be at work. He asks her why she's not at work, and she responds:

I've/I'd been working late this month, so I told my boss that I needed a rest or else I would have a nervous breakdown. He told me that as of today, I could go on paid leave until the fifteenth of next month, so here I am at home.

The argument for the past perfect continuous "I'd been working" is that she had been working late before her leave started. As of this morning, she's no longer working late.

The argument for the present perfect continuous "I've been working" is that her working late has only just finished, so it's still kind of a part of the present.

Is either tense correct in this case depending on what the speaker has in mind?"

 

[5jj]

Is either tense correct in this case depending on what the speaker has in mind?"

It is.

 

[emsr2d2]

Although I agree with 5jj that both tenses are possible, I would expect:

I've been working late this month, ...
I'd been working late that month, ...

The use of the present perfect suggests that the speaker is talking about the current period, so "this month" fits.
The use of the past perfect suggests that everything they're talking about was in the past, so I'd use "that month" to move the month away from the current month.