Many pups pee when they are really excited so if he is peeing, for example, when approaching people for a fuss, then is it more than likely excited peeing.

If, however, he is just peeing as he walks when he is not over excited, I'd bring that vet appointment forward and get him checked out. I'd also try to take a urine sample along for testing as it could well be a UTI

Some dogs adjust easily to potty training while it takes time for others. You just have to be more patient.