bearded dragon not eating?

Question
hello.
i got my bearded dragon for about 4 weeks now and he's approx 5 month old  and just over 11inches.
since we've had him he seems well and has been eating like a monster (15-20 crickets a day plus a variety of veg) and we had him checked up 2 days after we got him and the vet said he was very healthy.
althought the last 3 days he hasn't eaten anything (part from yesterday where he ate 2 crickets) he seems his normal self but i was wondering if it is normal for them to go through stages like this or whether its something we need to get him to the vets for?
he's just finished shedding a couple of days ago ( don't know if this could effect it).
we've also (last week) changed his flooring from what looked like large grains of sand (this was provided to us from the pet shop) to play sand which we brought from homebase.don't know if change of enviroment could have stressed him out?
also he hasnt pooped the last couple of days when usually he has 2-3 a day.
sorry to overload you with information buti just want to know if its anything serious.
if you can help me it would be great!
many thanks kirsty

Answer
 Ooooh, there's a number of things it could be.  First, you took him to the vet two days after you got him.  Normally, your "well-beardie" check-up should happen about 2 weeks after you get him, so that if he has relocation stress, the effects of it (parasite load increases) could be more easily seen by the vet.
 Another change in his habitat, is another thing, although the change from the deadly "reptile sands" to playsand is a good move.
 Then, there has been nationwide climate changes that have been making lots of beardies go into "brumation", a sort of semi-hibernation, but in your case your beardie is too young for that.  But he may be affected by the climate anyway.
 So, what you should do is make sure his temps are good, 100-105F on his basking area, 70ish on the cool side.
 Then, since you have already had him seen by the vet, bring the vet a fresh poop sample to check for sand consumption and any rise in parasite load.  If it's all clear, then, chalk it up to climate, or discomfort from his shedding.