My dog sways back and forth? Rubs nose on ground? Neurological problem?

So I found my dog swaying left and right before he eats his food and rubs his nose on the ground. I always interrupt him while he is doing it but never really actually saw him eat.... He only does this wen no one is there. When I call his name or interrupt him he stops. I secretly go away and he starts doing it again. Anyone know what the problem is? Please ad thank you!