I am really glad that you are able to switch pediatricians.
I remember when I was a new mom, too, seven years ago. The doctors had so much sway. They all pressured me to give a bottle to supplement breastfeeding because my DD had reflux and they felt needed to get her weight up. I trust that they were trying to help. And it made me question my decisions. Ultimately, I realized that I was committed to breast feeding and that my daughter's reflux wouldn't be helped by adding artificial products so early. She is fine today, just naturally thin.
Anyway, as you "get older" as a parent, you will be able to pick and chose more from what a doctor says and you will grow in confidence. The rest can just roll off your shoulders.
I found that this site had a huge amount of good information for helping me discern what was right for my family.