Welcome to the forum rockarolla!
It is really hot where you are living? The puppy may just be too hot so the floor is helping cool him off.
Did you talk to the breeder and see if they kept the puppies in the bathroom? Maybe it's just familiar?
Are you crate training? If it's not a temperature thing, a nice safe crate in your bedroom will be healthy and start the bonding process with you.
Lot's of great puppy tips here --> GSD Puppy Primer Tips
MACH3 Bretta Lee Wildhaus MXG MJG MXF MFB TQX HIT CGC TC
Glory B Wildhaus AX, AXJ, XF
"Behind every great man is a woman rolling her eyes." - Jim Carrey