He is 11 weeks old and refuses to be very ever be alone. When I'm in the room with him he will bite his toys and run around and the same with outside but the moment I get up to do something he comes running after me even when I try to tell him to sit. And if I do manage to leave he just wines/bark and scratches the door like crqzy . What do I do if I can't leave him alone ever even if his toys are out.