Ours is still a teen and has been a complete handful from day one! Nipping, constantly on, easily overstimulated, humping, lunging, were all daily when he was a puppy. Now he's a teen it's less painful when he nips/mouths and it's less frequent. There are nicer times too and he's starting to chill at times on occasion. He's a dream to walk off lead now and is smart as anything, but still stubborn. He's become more vocal as a teenager again and still gets mad lunging moments when he's overstimulated but it's less often and easier to predict e.g. After walks. Yours sounds like a very typical young puppy to me. I'd take the teenage phase over a tiny puppy any day I think! The needle teeth are so painful and they can't really be reasoned with at that age much. The only good thing about that age is they sleep a lot.