The lactation consultant suggested she was pulling off half way to try to control the flow - her weight gain seems to be fine. My second child is now 7 weeks old. I too, nursed my first child with only a minimum of diffuculty. I suffered from mastitis during my first week home, and cracked, very sore nipples for the first 3 weeks. My son still has some difficulty latching on at this point, however all else is going well.
Most mothers experience sore nipples.
I had such terrible pain during the first three weeks, I had to use my breathing techniques in order to focus on something else whenever my son nursed. I also bought a very good breast pump to relieve the engorgement. I have found that doing Kegel exercises during this time was also a great way to distract myself when the pain was otherwise unbearable. Tanactic acid, which is present in ordinary tea bags, is also great for toughening up your nipples. The tea bag trick worked the best for me, but a combination of techniques is probably best.