Hi Stacey,
Having three children with forms of communication/speech delays, this is something with which I am very familiar. Your daughter could be perfectly fine, or it could be the start of a delay. If you are concerned (no matter what the pediatrician or anyone else says--trust your maternal instinct), I highly recommend getting her evaluated using your state's early intervention services. You can find the NH link for Easter Seals here:
http://nh.easterseals.com/site/PageServer?pagename=NHDR_e...
If they are anything like the CT Easter Seals, you will love them :) Call to make an appointment for a developmental evaluation. Tell them your concerns. The professionals (usually two) will come out to your home or her daycare, assess all her domains of development (some aspects, like social development, require your input) and score her using various scales for typical development. If her scores come back with any significant delays and/or areas of concern, you have the option to set up continuing services where EIAs and various therapists (speech, occupational or physical) will come and do visits, depending on your daughter's needs.
I highly recommend early intervention services. As a mom, I can tell you it makes a big difference and the kids love it; as a preservice teacher, I can tell you that the more people you have working toward your daughter's education, health and well-being, the better. I highly recommend Easter Seals, too; they are kind, professional, and my kids all love them. My four-and-a-half year old still asks me to visit his teacher Todd, who stopped seeing him regularly when he turned three!
Good luck!
--M.