Initially I am alarmed at what you have to say, because she is not eating as often as you think she should and that she is sleeping "loads" during the day and a long time at night. Also, the bit about being somewhat underweight is troubling. Typically for a newborn eating infrequently and sleeping a lot are red flags that the child is not getting enough to eat or may be dehydrated. However, your daughter is 14 weeks, not 4 weeks, so it's possible she's just a content little buggar.
How can you tell? Check her on the weight charts (the new ones by the WHO posted at the top of this board). The idea is for her to continually gain weight at an
acceptable steady rate. Regardless of what percentile she's in, she should stay there as she grows. If you have a significant drop from one percentile group to another, that is the signal of a problem. Charting your daughter over the past fourteen weeks, how does she measure up?
Also, check the number of wet and poopy diapers. Poopy diapers may have dropped significantly due simply to her age, but she should still be having plenty of wet ones.
Also, how is she during her awake times? Is she alert and happy? Does she interact well? How is she doing on developmental milestones?
Are you logging her days? Do you actually know how much she sleeps, how long she is awake, how often she eats, and how long she takes to eat? If so, can you post this info because it would help. If not, I would recommend doing so. The reason is that one person's version of 'sleeps all the time' is another person's 'she sleeps ok'.
Check out these links for more information:
http://www.kellymom.com/bf/supply/enoughmilk-older.htmlhttp://www.kellymom.com/babyconcerns/growth/weight-gain.htmlhttp://www.kellymom.com/babyconcerns/growth/index.htmlWith a birth weight of 6lb, 11oz your daughter should be about 11lb, 9oz by now, according to the above weight-gain guidlines. I would't go all crazy about a 3oz difference. Just make sure this trend of being underweight doesn't continue.