My Dog.....

I am an animal person.  I love all creatures.  Currently, I have a dog, a cat, and two ferrets.  And they are all having issues!
The cat has started to claw the furniture since we moved.  Never happened before.  And he is almost 8 years old so it's late in life to be starting this habit.  My fiancee keeps hitting the roof over it, and I understand.  Our new furniture is all wrecked because of my cat.  I don't know what to do with that.
Then there are my ferrets.  One is sick, very sick.  We took him to the vet three times leading up to his sickness and were told to 'keep an eye on it' but no vet did anything.  Now that it's to the point where something should be done we don't have the money to take him back to the vet.  I feel terrible about it.  I'm keeping a really close eye to make sure he isn't suffering.  If he starts to show signs of pain, then my poor credit cards are going to get an unhealthy dose of spendage.  And the illness is most likely fatal.
And then there is my dog.......sigh.  We have a 7lb chihuahua.  He has never been that well house trained.  No matter how hard we tried he refused to get it all the way.  But we have always been able to control it.  So we move, we have a fenced yard.  For the first month he pees inside a little because there was another dog living here before him.  Then for two weeks there is not one single accident inside.  But then he discovered how to get out of the yard, and bylaw brought him back.  I was spared a ticket because it was obviously an accidental escape and no intent was gleaned from it.  But I was told if he got out again that we would be heavily fined.  He is a small dog, and we are having a hard time kongo proofing the yard.  So a leash is our only option currently.  But since we have started leashing him he has taken to peeing outside, and pooping inside!  He will spend an hour on his leash outside, then come in and poop on the floor.  I am getting so fed up.  I don't know what to do anymore.  I smacked him today, and I felt so bad.  I actually cried.  Now he cowers when I go near him.  It's not fair to him that I got so angry, but I can't seem to get him to go outside anymore.  I am at such a loss, and I feel so defeated.
I have never hit an animal before.  And this little creature, who cannot defend himself is what I decide to smack?  I'm a terrible person for doing this, and if I believed in God I would ask for forgivness...but since I don't I cant. 
What do I do?