Having a young dog in the home is fun and at the same time can be frustrating. You have trained your dog and he or she seems to be learning what you have taught but then all of a sudden its like he has forgotten it totally . Yup this sounds about right, I have been there and understand it fully. There are several reasons why you might be seeing this revolt from your pup and learning those reasons can be helpful to your sanity.
Youngs dogs need their rest and plenty of it. So consider what activities you have been doing with your dog and whether he or she has had an opportunity to rest. Dogs who havent gotten enough rest dont do well, they get antsy as if they need more exericse when in fact they need a nap. Then there is the reason of did your dog get enough exercise. This can be a combination of physical running, toys that have given him the opportunity to play by himself or with you and the chance to learn through training. The latter doesnt have to be terribly long sessions they can be as short as 3 minute sessions repeated throughout the day. Another reason can be is your growing dog is getting bigger and is he getting enough food, did someone forget to feed them, or does he need just need more food. Yup dogs can get hangry and will act up when they are and just will not concentrate on anything. Or is he thirsty. Biological needs often take over so even the need to go potty could be a reason for not paying attention. Maybe your dog needs to chew on something to relax him or her or just that satisfaction a good chew gives them or allowing the chewing to calm them down for a good nap. Does you do know how to settle but there too much going on in your house where the dog is having trouble calming down? Having a doggy sanctuary can be a good plan where he can have some quiet time, a nice comfy dog bed, some soft music is a recipe for a good nap so that when he wakes he is ready for orders.