is my bearded dragon sick???

Question
please help, i think my bearded dragon is sick. his beard has been black the past two days and the rest of his body light in color. he refuses to eat, even his favorite snack that he NEVER turns down. he doesnt move much and when he does he seems unbalanced and plops himself back down. his poop is runny. im not home during the day so i dont know his behavior from 7am-3pm, but i dont think much is different than what ive seen. im very concerned and need an expert's opinion. please get back to me as soon as you can.
Thank You
P.S. im trying to ask multiple experts to see what answers i get, i really need help!

Answer
Hello Carissa,

I am sorry your dragon has a black beard.  
How old is he?
Which UVB light are you using, a fluorescent tube bulb or a compact/coil light?
How old is the UVB light?
Do you give any calcium for him?

It sounds like a nutritional issue to me.  
Runny stools also indicate parasites/worms which can affect his health.  I would suggest getting a fecal done to check his levels.
How long has he been ill?
Is he losing weight right now?  If he is losing weight, I would start feeding him baby food to help him out.  Use a plastic dropper & a syringe by dripping it onto the end of his nose.  

What are the temperatures in the tank & what type of thermometer do you use?
Do you have any pictures of him?

Let me know how he is doing.
Tracie