Crickets will burrow into the substrate most of the time if uneaten. I believe your frog needs to see a vet. I think due to you using tap water that was not treated and de-chlorinated for such a long time has finaly taken its tole on your frog. You could try and soak your frog in some warm water with a little epson salt not very much maybe a quarter of a tea spoon or less in the water. Your frog is very ill. I really REALLY suggest taking him /her to a vet now. There isn't really anymore you can do until you find out exactly what is making your frog ill. If you wait any longer it may be too late. Far to many people wait until there frog is already on its death bed before taking it to a vet. Don't make the same mistake. Take him/her to a vet and let us know what is wrong.