All right, let's narrow this down a bit.
If you have a Mercury Vapor, your beardie needs to be an absolute minimum of 12 inches away from the light!! I don't know a whole lot about the rep pro- but the stuff I found implies that it is a Chinese made bulb and that the 60w isn't accurate and that it's more like 100w. First sign is that no company really makes a 60w self-ballasted MVB. If it is an external ballasted- then there is additional hardware and you cannot just screw the bulb into a fixture- additionally, the bulb will produce very little heat!
Either way- move that basking spot pronto!
That actually could resolve all your issues. That you just bought it and you recently started experiencing a change in behavior sorta points in that direction!
Additionally, let me strongly encourage you to get a digital thermometer with a probe. They are inexpensive. About $10-15 at a reptile store. And oh so worth it! So blood makes stuff go, right? Like your intestines, brains, lungs, heart, etc. Cold-blooded creatures need external heat to really get their blood going, which translates to really getting their system going- including their digestive system. (To a lesser extent, also true with humans- you know how you aren't supposed to eat right before you go to bed because your metabolism goes slower?) Without proper heat, a beardie can't properly digest his food. Not good.
Temps that are over 110 get dangerously close to being able to cause brain damage.
How did you relocate him? Did he change cages? Did you move? Some beardies are more change sensitive than others. My beardies both are handled by lots of people and often go out with me (on their leashes, of course!) and neither have ever blackbearded or refused food on account of a change in their surroundings. I suspect relocation stress largely results from beardies who are very young or have not been handled much, etc. Obviously there are exceptions to every rule- but I'm bettin' that's where most of it comes from.