bearded dragon is not acting normal

Question
my bearded dragon is around 6 months old and has recently stopped eating crickets or worms, he still seems to like his lettuce but thats it, he stopped pooping and seems to act frantic in his cage and is always up on his back legs scratching at the glass like he frantically wants out, some have told me its normal behavior but it just seems strange and he seems upset about it, i really dont wanna pay a huge vet bill to be told hes fine just acting odd but i will if this doesnt stop or if mabey you also feel its not normal behavior

Answer
 At 6 months old they hit puberty, raging hormones.  He wants out to hunt females.  As they grow older they eat more plant than animal but he's so into his hormones he's not thinking of food.  I would tell you though, lettuce is not good food.  He needs more nutritious greens.  Collards, dandelions, turnip tops, mustard greens and arugula are the more staple greens, full of much needed calcium and vitamins.  But for his age, he's a normal beardie.