You're little frog needs to get a vet ASAP! I would call your normal vet and ask if they treat frogs and if not they should be able to give you the name of someone that does. In the meantime you should give him a pedyalite bath. 1 part pedyalite to 10 parts warm spring or treated water. This will help perk him up a bit. Don't let him sit in the bowl with crickets crawling over him, the crickets will bite him and cause more problems. If he won't hunt on his own try tong feeding him. Make sure the crickets are dusted with calcium. Lack of calcium could cause muscle weakness and bone loss. When you do bring him to the vet, try to bring a fecal sample too so that they can check for parasites.

I struggled with bringing my frog to the vet for the first time, people thought I was crazy and kept saying "it's just a frog" but we chose them as our pets so it's up to us to take care of these little guys. Trust me the vet won't laugh at you, they told me that people actually bring fish in!

Good luck, I hope you can get some help for froggie.