if this is a new thing that hasnt been a preexisting problem, you need to look for a cause. it could be physical, talk to his vet and be sure to have him checked out. it may be an emotional problem he is dealing with and he cant tell you in human words. animals are just children that never grow up. but they do grow old, old age symptons in dogs can be very severe before they leave us. im not sure off hand the life span of a belgian sheepdog but im sure you would know if it might be age. just like with a child that starts a strange behavior you have to first rule out a medical problem and then look at other areas. changes can be tramatic for any animal. even a small change that you dont think about. example: a dog has been eating and drinking at the same place in the kitchen since a pup, move his food and water dishes and watch how upset he can get. move their bed, it upsets them unless you do this regularly. and its worse in an older dog. they cant tell us in words but watch them they will let you know. i hope this can help alittle.