I have a small Hawaiian Snowbush that I rescued from a local nursery. It was a failed bonsai attempt and in pretty bad shape when I got it. It lost even more leaves when I first brought it home. I gave it some Superthrive waited a couple weeks and repotted it. It recovered nicely after a few weeks longer and started putting out loads of new growth. I have mine in morning sun only and allow the surface of the soil to dry between waterings. I've had it for about a year and it bloomed for the first time in Jan. The flowers are tiny and the same colors as the foliage so they are easy to miss. Your plant is probably going through some transplant shock. I'd give it some Superthrive or B-1 and see how it does. Don't over-water it or the leaves will yellow and drop.
Karyn