So you're saying you palpably felt when you woke up like you had just lived for days? You had experienced every minute of those days?
I said nothing like that, and no one dreams with such detail.
Or are you saying days passed by? Because days can pass, but the moments within the dream in which you're "doing something" most likely did not add up to days. In that case, it would be "doing something for two minutes, then it's the afternoon, and you do something for five minutes, then it's the next morning and you do something for three minutes, and it's a day later." That's not actually having days experienced in your dream, just days pass by.
Probably that's how it works mechanically, as REM states are only 15 minutes max, but the perception is - and everything about a dream is just imagination/perception - that it lasts far longer.
So many times between 5-minute snooze cycles on the morning alarm I dreamt I went to school or work, attended full classes, had some wild adventures, etc. then woke in a panic thinking I missed the whole day and find it's just a few minutes later in real time and I actually still had to live my day. Then I'd get depressed 'cuz it was like going to school or work twice in a day - that's how real and detailed it was.
Anyone can recall a 2-week vacation in very elaborate detail with just 15 minutes of thinking about it, especially if there are visuals to help. "A picture is worth a thousand words" and who knows how many minutes of perception.
That's what the film is playing on, quite factually. Any 1st year psych student has probably read numerous studies on same.