Resort- the same thing happened to me. Too far along to make a change. I was early stage triple negative and 72 in good health. I was given CMF pre surgery only to learn through 2nd and 3rd opinions that there is no approved treatment after surgery if CMF is given (an error by my initial breast center). I had to consult several excellent hospitals for the right treatment option following surgery. It was determined I should receive taxol/carboplatin. I should have had Zeloda (a pill), but instead had another 12 weekly rounds of chemo.
Keep asking questions until you are comfortable with the answers. Wishing you the very best.