Re: Sleeping too much??
Let her sleep, mama. Some babies do sleep through, and as long as you nurse on demand it's to follow the baby's lead. Especially at 3 months of age. It would be different if she were a newborn, but at this age I think it's really fine. And your supply will adjust after a few nights, maybe a bit longer.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"