Help! GBB not eating, losing weight (not molting issue)

Well to be honest, it may be molting, but I know a lot of newbies freak out when their T is about to molt...I don't think that's the problem though...

He hasn't eaten in a long time, and is very lethargic. He also seems to tremble a bit when he walks...any advice? He used to be super active, and a very agressive eater, so I'm kind of worried. The only thing I can think of is the substrate was quite moist for a while. I was thinking it would dry out quickly, but I was wrong. I've since changed the substrate, as you can see from the pictures...

Put a water source in there? Sounds dehydrated to me.

Yeah well like I said, it was really damp, and that's when he stopped eating. I've only recently changed the substrate...

Try a water dish.

If he's "trembling" it sounds a little bit like DKS.

What is that white thing between its first and second leg base on the left side?

Bad news. I found him dead last night

Not sure what happened, but I think it was probably related to the humidity...