See a lactation consultant and go to a la leche league meeting. The emotional and moral support is wonderful and they will have some good suggestions. I think a lactation consultant will weigh the baby before nursing and after, so you can see how much she is really getting. Its terrible worrying that your baby is hungry because you are doing something wrong. They will help you.
Is your baby gaining weight? If she is, then that takes a little bit of the stress off.
My son did this same thing, but it was because I had the forceful letdown and my little guy was choking. He could only nurse when he was sleepy, or when the vacuum was on (two situations where he nursed more slowly) until he was about 3 months. He became a champion nurser, and I nursed him until a year, when I had to stop for other reasons.
You can do it. Having a two week old baby is really hard and tiring and stressful and your hormones are all out of wack - things will get better.
Contact a lactation consultant (I think one will come to your house for about $100 - or I talked on the phone with one for hours and corresponded via email and she charged $50) and go to a la leche meeting.
Good luck, mama!