I responded on the other board as well:
I will tell you that you are describing my eldest daughter almost perfectly except she would sleep all day and do what you are describing ALL NIGHTTTTT!!! It was torture and i seriuosly didnt want anymore children after those long couple of months.
What switched my daughter around was having her adjusted by the chiropractor. She had some trauma done to her atlas vertebrea amongst a few other things from birth. That was the first night that she was able to sleep somewhere else then our arms! Granted she is still a horrible sleeper at 2 and was never the picture of blissful night sleeping (didnt sleep through the night til she was 18 months old) butttt it was much more manageable and i was able to continue breastfeeding! Good luck