Problem with my new oak tree

[GreenMommy]

We received an oak tree as a memorial tree to honor our daughter and we really don't want anything to happen to it. It is about 20 inches and we planted it in a ceramic pot. The leaves have little holes and some brown spots and a little bit of white. I don't know much about trees and hoping someone could help figure out if this is a fungus and what I should give it. Any help is greatly appreciated.