Hi I planted a newly purchased nectarine tree on 5-11. today 5-22 the trees green leaves have dropped.  I cannot say that the tree looks dead as the limbs are not the color brown.

I planted the tree per the label attached to it.  2 times the size of the pot it was in.  the junction was just above ground, root ball loosened up and ground replaced and watered with 

5 gallons of water.  the tree has been consistently watered since.  Is there a strees period of the transition of the trees plastic pot to the ground where they lose their leaves?  is it 

dead as the other one I bought with it has its' leaves?  should I give it more time before I refund it?  I know I did things right.