My baby bamboo seems to be dieing and I need some help figuring out what's wrong with it. Can you help?

It was sent to me from a nursery, and they say it's just from shock from the transportation. The leaves turned yellow and fell off; all of them. I have it transplanted it in potting soil mixed with gypsum pellets, sand, and organic fertilizer, and have small rocks/pebbles on the very bottom for better drainage. I also have it on a raised platform/water catcher for air circulation. It is a black bamboo, and I have it in plenty of sunlight; the soil has also been consistently damp since I've had it.