E.M.
Hi Momma-
I am so sorry, that is incredibly frustrating! Usually it's the other way around- they go to the bottle and won't go back to the mother. Hmmm. I know you have tried different nipples, but you may need to try a few more. My sister found that the dark yellowy brown ones by platex were by far the softest, they had the best flow, and her baby didn't fight too much before he got used to it. The nipples, too, may have either too much or not enough flow and so she is frustrated. It's hard to gage which one is right, but when they start eating at a happy pace, then you know you have the right one....until they grow and then you need the next size up.... My other sisters have boys, and a couple of them were very small when they were born. They had to use the dr. Brown's bottles, which were super pricey, but for some reason it was the only one they would take. It is frustrating that each mother has to try, hit and miss, to find that one, perfect bottle that their baby will take, and no two kids are exactly the same. Sigh. I think, if you call the advice nurse or your pediatrician, they should be able to give you some pointers, like rubbing the milk in her mouth with your fingers to stimulate, etc.
I hope that helps some. Good luck!
-E. M