missy, you've gotten a lot of great advice! as i am going through a similiar situation with my ds re: weight gain, i wanted to share what i've learned so far.
1) you've heard this already but it bears repeating: most doctors know SQUAT about bfing. take EVERYTHING they say about it with a HUGE grain of salt. the vast majority are NOT experts and any 'advice' they give you is really just an OPINION (and usually an ill-informed one at that). the stupid scale is NOT the most important measure of wellness, despite what the docs want you to think.
2) not all IBCLCs are created equal. i know that many people here rec. that you talk to one, but i must say that i have not been impressed with the 2 that i have talked to. the 1st IBCLC agreed with the doc that i should supplement w/ formula and did not EVEN ONCE suggest that i increase nursing sessions, look into herbs and/or prescriptions to increase milk supply, or even say that if i did supplement, i should use a SNS. so i ignored her advice and found another IBCLC. i saw this one in person, asked her to check the latch etc. she 'checked' the latch by sitting 3 feet away and looking while i bf'd and pronounced that it was fine and that i should supplement with formula. again, no mention of increasing nursing sessions, reglan, domperidone, or SNS. so the lesson here is, even having the int'l bd. cert. does not ensure that you are getting good bfing advice.
3) THE ONLY EXPERT ON YOUR BABY IS YOU! don't be afraid to trust your gut, as many of the ladies here have suggested. i think too often we moms look to 'experts' to tell us if our babies are doing well, when in fact our hearts usually KNOW whether our babies are well or not. if you need medical advice to back up your own observations about your baby's health, dr. jay gordon (www.drjaygordon.com
) and dr. jack newman (he has a website, too, i'm sorry i don't have the address in front of me) both go by the mantra "look at the baby, not the scale". they might be good sources for you to mention to any peds you talk to.
i know it is hard to ignore the 'numbers' but trust your heart.