I dream during 7 minute naps

Could be a milder case of narcolepsis.

REM (Rapid eye movement) is when you dream. REM happens when you first fall asleep. So chances are when you sleep and wake up not long after, still being in REM state you remember your dreams more often. Everyone dreams during REM, just not everyone remembers them. :)

Look into the Uberman Sleep Schedule, it'll tell you why you dreamed in such a little time.

You just have an irregular slepp pattern. Your entering your first REM stage early and it is also stronger then other peoples. It's also possible that your not completely sleeping and it's a day dream.

You should eat more.
Lack of food has been proven to cause vivid dreaming.

(:

Happens to me frequently. I pretty much dream as soon as I fall asleep, even if I'm only asleep for like 2 mins!