Loss of Appetite
If your bearded dragon suddenly stops eating any food you offer it, that could be a sign of stress.
Try offering some insects or fruits that are considered treats, such as waxworms, mealworms, papaya, or mango.
If the beardie still doesn’t take to those foods, then you may need to check the temperatures in the terrarium.
Make sure you have a basking area that is at least 90 to 110°F, depending on its age. Use a high quality temperature and humidity gauge to ensure proper basking and cool zone temperatures. This isn’t something you want to guess at!
If the temperatures check out to be adequate you may need to contact your veterinarian.
Lower Activity Levels
If your bearded dragon seems sluggish, and does not appear to be as active as it once was it could be a sign of stress.
Again, check to make sure you are providing adequate heat and full-spectrum lighting. A diet that consists of improper nutrition could also be the culprit.
Always offer a well-balanced diet of mixed vegetables and feeder insects. Remember to sprinkle calcium powder with vitamin D3 on each meal, whether it’s feeder insects or vegetables and fruit.
reference from this website:http://www.beardeddragoncare101.com/stress-bearded-dragon/
hope this helps and hope your beardie gets better soon