Listened to a song on repeat last night, now it sounds different?

I fell asleep last night at half past midnight with a song on my iphone on repeat. The song is called Only Love by Paris, or PVRIS. You can find that on YouTube if you want to see if I'm just hearing things. When I woke up at six thirty, the earphones were still in, the song was still playing, only it sounded completely different. It sounded really acoustic, like her voice had more emotion in it; before it sounded normal, like she recorded the song and the studio people fixed any problems and made the voice sound better. The piano keys also sound different, like completely different tones, the guitar chords sound different, there seems to be some sort of xylophone sound playing in the back ground during the chorus. Her voice seems to have more echoing, and as I said before, her voice sounds way more acoustic, more emotional. I've listened to the song several times today, with headphones, without, in my music library, and on YouTube, to see if that's the problem. It's not. What is this?

Have you ever had a favourite song that you listened to so many times that it just doesn't sound the same and you eventually start to dislike it? Or heard a song that you didn't like the first few times, but grew to like the sound of? I know this really doesn't help, but I guess it's just the way out brain works.