Kennel him in a crate if you're gonna leave him inside while you're gone. Do not feed him in the morning, feed him right when you get home. Make sure the crate is small enough for him to stand in, but not much else. They USUALLY will not mess where they lay.
That's my best suggestion. I've potty trained ALOT of dogs.
Krystale, the problem im having is he is potty trained, but the last month or so hes forgotten all of it. I have his old crate, im just gonna have to start puttin him in it, but id rrather come up with an idea of why hes doin it.