How to revive newly planted apricot tree?

[perth9223]

Hi all,

I am relatively new to gardening and certainly not an expert. I planted my first apricot tree a few months ago (bare root), and it all looked pretty good, it started growing leaves, but recently it lost almost all of them. The remaining look like this:

What could this be? Is this some sort of a disease? 

Thanks in advance!