My late mother who passed away due to a 25 year Breast Cancer bout was unable to breast feed my brother and I. Many years later it was first diagnosed that she had Breast Cancer. Unfortunately, her father did not know at the time when she was an infant the hazards of second hand smoke. Fortunately, my late grandfather never smoked around me;my late grandfather learned by that time the hazards of second hand smoke. Also my doctors told me that I am lucky that my mother wasn't able to breast feed my brother and I because it is meaning that the cancer wasn't transferred. I still need my breasts to be checked by my self examination. and get proper regular breast screening with a doctor and a Mammogram. Your town can do a breast screening exam for free. Please, I urge all to consult a doctor immediately and do some testing if breast feeding is a problem. It is best to just rule out if there is a health issue.
I hope for all good health for your infant and you!