When the day is more than one week old, referring to it as a day of the week (Friday, Thursday ...) may not be a good idea. Just call them by its date to avoid potential confusion.
Yes, that's true, but the problem is that native speakers very often don't just refer to dates in that way, so learners who speak with them can easily become confused.
In fact, I didn't know the exact date when I had the conversation with someone. The only thing I could remember was it was on Thrisday and it was three weeks ago.
I'm giving you the date because it's easier for our discussions. I will be glad if you can give me some hints.