Is she eating enough - gaining weight and having enough dirty diapers? If so, then don't worry about it, she'll have more wakeful periods as she gets older...and you'll want her to go back to that sleepy baby!
Warning
No formatter is installed for the format bbhtml
Re: 3 week old sleeps all the time
Seriously - enjoy it. Soon you'll be fighting to get your LO to sleep. Trust me.