Dead or molting?

I don't know much about scorpions. I have an Arizona Bark Scorpion, we feed him crickets. He's usually very active (especially at night) and lately, as of the past week, he has become "sluggish". A cricket can stay with him up to a month before he eats it, so nothing seemed abnormal at first. I first noticed he would fall on his side, his tail seemed very hard and almost like he couldn't support the wait of it. I tried to stimulate him (which may have been bad I found out), when I would his legs would slowly move. He was in this slow moving state on his side for about a day and a half before I decided to isolate him, take the cricket out and move him away from other animals. As of a day ago he hasn't moved at all, his tail is still stiff, slightly curved, but his legs are curled in and his claws are limp. I don't know if him still glowing under black light means anything? I was told some scorpions molt on their back but I'm afraid I've tampered with him too much. Is his tail being hard still a sign or anything? Please help!

(I would post pictures but I can't figure it out...)

Unfortunately it sounds like your scorpion has probably died. You can generally easily tell if a scorpion is about to moult as it will become very fat in the weeks/months before moulting. It will also dull in colour, cease eating, become less active and may burrow or hide away. It will however still have reasonable mobility i.e. can, if very stressed, walk and will flick metasoma, right up until the hours when it actually begins to moult. Here's a good thread on identifying pre-moult scorpions [HOW TO] What is "MOLTING" and "PREMOLT" in Scorpion Context

Dead scorpions continue to fluoresce under UV light.

As a side note, I wouldn't recommend leaving crickets in your scorpion tank for a month. If a scorpion is hungry it will almost definitely eat any prey items you offer it within a day. Any prey items still left wandering around after a day should be removed from the enclosure so as not to stress your scorpion. Try offering food again a week or so later, unless of course you notice that it looks to be coming up to moulting, in which case stop feeding altogether.