First time owner/weird looking poop etc

We just got our first (Fancy) bearded dragon. I'm not sure if it is a male or female, we got it from a local Pet Smart and they hardly provided any information about it other than its about two months old and what to feed it. Ive looked up ways to determine the gender and all however, we just got it less than a week ago and I know its very stressful for them to move tanks and everything so ive been too scared to check because I didnt want to cause any more stress for it until its settled.
We started with feeding it crickets and the juivenille beardes dragon food because thats what they said the let store had been feeding it. A friend of ours suggested some millworms, and we bought some and fed it a few... It really seemed to love them... Then all of a sudden it kinda stopped eating the crickets and all. I read online that it was normal for them not to eat for up to a week if they were stressed so I wasnt too worried. But this morning I went to switch the lighting from the dark light to day and I noticed its poop was different than it had been...or at least I think its the poop. So I cleaned everything up and got fresh water and a few crickets and some fresh food. And I went to check on it to see if it decided to eat and all and as suspected, it hasn't, but there was more strange looking poop in there and I tried to look it up and couldnt find any posts or anything similar to what it looks like so I decided to make a post to find out if I should be concerned or not.. I was thinking it was due to the millworms that maybe they had upset its stomach or something since it hasnt ate since he ate those.

Hello,

That is most likely due to the mealworms, I agree. It looks very dry & to possibly have some
shells in it, but hard to tell.
What are you feeing him now? I would try to get some oral fluids into him also to help out in
case he is a bit dehydrated, too.
Does he have a good appetite?

Tracie