getting big already

So when we went to the doctors appointment today they weighed Riley and I could not believe it. When he was born he was 6 lbs 15 oz and drooped to 6 lbs 10 oz when we left the hospital. They say that babies should get back to their birth weight within 2 weeks. well Riley is 11 days old and he weights 7lbs 6 oz. He is getting so big. he now is fitting into most of the newborn clothes and no longer needs the preemie clothes or diapers. wow I can't believe it.