No. You are, in fact, taller.
This is due to gravity. Think about it; when you lay down, gravity is pulling at you horizontally. This is why you are taller when laying down. During the day, gravity works at you, squeezing you vertically and making you shorter.
They LIE down (to lie, lay, lain). LAY the table, please! (to lay, laid, laid).
Get Down or Lay Down was created in 2000.
Lay Me Down was created in 2010.
It is not a combined form. The word "down" is an adverb. It can modify verbs such as lay.
The past tense of "lie down" is "lay down."
You can't lay down in clubpenguin. Sorry.
The past tense of "lay down" is "laid down."
"lay" is a verb and "down" is an adverb.
As I Lay Me Down was created on 1995-02-07.
Lay Down was created on 1972-10-13.
Lay Down Beside Me was created in 1979.
Lay Your Troubles Down was created in 1989.