I think her behaviour is normal

Mine did exactly the same from about 10 weeks until almost 6 months old and its a stage that I really miss now

They could play for ages and seemed to go inta a hyper mode where they would throw their toys into the air and beg for us to join in,it was so much fun!! Jess was really hyper and would play with anything,she would just go into her hyper mode and grab what ever she found in her path and make it her toy..then all of a sudden she would crash and sleep for hours! lol.
I would make the most of it because soon they dont play as much as you will be wanting a puppy all over again lol.