My son is 4 weeks old, and after his two week check-up he had not regained his birth weight (born at 8lbs 8oz, at 2 weeks was 7lbs 12oz). I was EBF, and my Doc ask that I give him 2oz of formula after I nurse him to help him gain weight. I didn't want to give him formula, so I started pumping and giving him breast milk after nursing sessions. He gobbled down the bottles and has progressively taken more and more in the bottles (from 1.5oz at the beginning to almost 4oz now). I also had extremely sore nipples and sought the advise of a lactation consultant at 3 weeks. She helped with the latch which is now good on the left and still painful on the right. She also suggested I continue the top-offs with the bottle due to my son's inadequate weight gain in the first 2 weeks. He has gained weight well since then (now 9lbs 10oz), but he is now impatient at the breast and cries and thrashes about after 5 min on each breast. My left nipple is still very sore, and I'm in pain while nursing on that side. Our nursing sessions have gone from 15min on each side to barely 10min. My Doc doesn't see a problem if he is gaining weight, but I'm sure he will reject my breast all together for the bottle if things continue this way. I plan on going back to the lactation consultant, but would love some advice in the meantime. I really want to nurse my son for the long haul, but I keep running into problems.