Try some well fed crickets since he is "said", so young.
It may be a couple of issues regarding stress. Make sure the temps are ok, make sure he has water, and make sure the food wasnt to much for him to take at once along with beeing void of any disturbances. That happens alot with baby Leo's and mealies even I the cricket hater will admit that they are not the best for little guys. But dont just stop unless the worms are to big, I have seen Deathco. ( where the pets die) sell some realy small mealies that should be no problem but that many sounds like to many for that young of a Leo. Give about 2 every few days and some crickets.
I doubt it was pooped, I can place it on beeing thrown up.