L.M.
my baby girl had the SAME EXACT problem. And I also tried everything you listed. I finally ended up going to a doctor to help me figure this out. He told me to get laxatives for her....however mine was about 5 months....not 6 weeks. I'd call your pediatrician, see if there's anything you can give her.According to her doctor, my baby girl needed to get acclimated to the soy and her digestive system needed a little time so it was a waiting game. we watched her closely for about 3 weeks and FINALLY she took to the soy. Alimentum didn't work for her cause she just didn't like it (my wallet was happy about that), so give it a try.