Question...

K when I'm really sleepy or when it's late at night, or when I've been sleeping and wake up and have to drive home or something, music that I know is supposed to be slow seems to go really fast... is this just me? Is it just my head trying real hard to catch up to the beat? I get o confused, and I'm all like, "This song is supposed to be waaay slower."
I was just wondering.
any answers?