I found a stray dog in the wilderness the other day and was letting him follow me around for a bit. I went to the Dark Brotherhood sanctuary in Falkreath and it said something about my follower at the top of my screen when I went it. When I left the dog was nowhere to be found so I assumed he went "home".

Later on I went to get my real dog from my home in Falkreath and it wouldn't let me because evidently I already have a animal following me. I tried waiting 72 hours but it still said I had a animal following me. I then tried to pick of the Clavicus Vile because I thought Barbas would replace my invisible dog and fix the problem however it didn't.

Really kind of annoyed because I'm already suffering from the Serana bug and now I can't even get my dog to follow me. Does anyone know of any fixes I could use?

It's the animal follower bug. I think you need console commands to solve it. (I guess you are not on the PC? )
Or try to find Meeko. I think Meeko should work, and after him, every other animal, too.
But only if you did not find Meeko earlier.

Yeah never use Stray dogs they are extremely buggy and disappear all the time unless they are always right next to you when you enter another cell. They even disappear if you leave them somewhere.

Thanks, Meeko did the trick.

Ah, very good.

Invicible doggies are so cute!!!!!!! I hope they include them in the next DLC, plus vamps with sixy ponytails!!!!!!!!!!

I'm sure this is Bethesdas top secret No. 1 on the priority list.