My dog is nuts

We have had our dog for 12 of it's 13 years on earth, and I have to say he has finally gone completely mad. Ever since we came back from our trip to Australia early last year, he has been acting very strange (or stranger than normal, I should clarify).

First issue is him crapping on the carpet. When we adopted him, he was already 1 year old and was house trained (my kind of dog). He was very good at holding it in while we were away at work, and only had the odd accident in the house. Now if you don't watch him like a hawk, he sneaks off into one of the bedrooms and takes dump on the carpet. Not good. In addition, he has trouble holding it is over the workday, so we now often come home to urine in the sewing room where we keep him when we are out (at least it's not carpeted).

Lately he has started to whine and moan every morning when we try to put him in that room to leave from work. He used to go in there quite willingly because we would always give him something to eat as a reward, but this doesn't work at all any more. Many times I have to pick him up and carry him into the room, and last week he bit me once when I did this, and he tried again this week.

He seems to have severe separation anxiety, and not only does he act up in the mornings, but is way too over-excited when we get home. He has recently tried to get behind the large freezer we have in that room like he is after something, and as a result he has torn up the baseboards. I guess dogs can go senile just like people, but we are kind of stressed with this. I am taking the approach that he is trying to challenge his place in the house, so both my wife and I are going to crack down on him to put him in his place. Things like ignoring him when we get home for 30 minutes, and if necessary flipping him on his back and holding him there.

I love the dog, but I have my limits. Sorry, just needed to vent.