I'm 8 wks post-op and I'm almost sure mine is shorter too. I'm actually glad about it. My right leg has always been longer and it's always tilted my pelvis. I don't think it's impossible at all. From a physical perspective, it could depend on the shape of the femoral head. Is it long and skinny, short and rounder, etc., etc. If the doc bevels it down to get it where he needs to and the cup is set in deep, one could easily lose a little length.
Rag, you're gonna be stiff and sore and will have some limited ROM for awhile. Dude, they just cut you open and spun your leg around to pop it out of place!!!
It will heal. Your swelling will deminish, and your stiffness and ROM will increase as you heal. That will take some time. 10 days, that's pretty soon. Heck, read on here. Some people aren't even able to put their socks on for a couple months. Be patient with yourself and your recovery.