Fine needle biopsy pathology showed aggressive cancer... had thy. removed after surgery report showed benign..?

I do not understand how this could happen... I am thrilled it is not cancer however I never would have acted as quickly as the two surgeons suggested (I did have second opinion for surgery) but did not get second for pathology and I am afraid that was a mistake...based on the pathology report I made a decision that to remove the entire thyroid... If I knew it was benign I would have only had half taken out.. The wrong decision based on the after surgery fact that there was no cancer. Sorry, but I feel like I have been cheated out of making the right decision for me because of it...