See if the temps in his terrarium are appropriate. If they aren't fix them. Also, reduce the amount of crickets you feed temporarily. If this doesn't change things quickly, see a reptile vet.
His basking temp should be much higher, like 105. It's likely that he is not digesting his food well. Have you ever noticed that he is passing undigested food?
What kind of lights do you use?
How do you measure your temps?
my beardie did the same but with meal worms, he ate too many, then he went and sat on a heat cave, he then threw up, on the viv floor, he is fine and and back to his usual ways. my female was quite concered with what was going on and wanted to look.
some of the mealworms were still moving. when they throw up try not to give them anything to eat and a small amount of fluid round their face, because the sick is sticky and can stick to their face