Bearded dragon turning black in color, won t eat, sleeping all the time, walking and attempting to hunt as if shes drunk, weight loss.?

My bearded dragon is four years old, she s never had any issues like this. Not only does she have the symptoms above, but she also is vibrating her head. She is not her usual self and looks as though she is in pain or something is very wrong. We feed her salad every day and always look to see what is okay for them to eat and not okay. We also feed her crickets. She has newer lights, we got them about five months ago. I don t know what could possibly be wrong.