I have found that GSD puppies are WAY more work than most other breeds.
To the extent that, frankly, when people see me and my GSD's and seem to want one I almost always do NOT recommend a GSD. Because they really don't understand that my breed may take WAY more time, money, attention, training, exercise TIME TIME TIME and help from going to classes.
And people that don't have GSD's and have raised other puppies really have no clue at our challenges.
Use the crate to separate the dogs.
Take time, EVERY DAY, to take your puppy out for an hours OR SO long walk. If there is some fenced in area you can play Chuckit or have the puppy really run it would be the best.
How has this training been going ---> Top Training Expectations for Puppies
Know you have to locate and sign up for some dog classes. The socialization plus timely help from a great trainer is something we just can't do on our own.
Good luck, you aren't crazy, your puppy is harder to raise then you parents. But that said, you got a GSD puppy and so now are dealing with all the NORMAL GSD puppy things. So just 'shoulder to the wheel' and start managing your puppy like it is a GSD and not one of those EASY puppies!!!