I am concerned over my 14 yr old cat.. all of a sudden he has been going under my bed... lying on his food dish for hours on end.. and now he is going to the basement to his litter box and lying in it .. can anyone help with this .. he is eating and he has been drinking... he isnt listless... when I get ready to go to bed.. I pick him up and take him with me and he stays on top of me until I practically push him off.. I dont know if this is a behavior problem or not.. any ideas?