Formula

My daughter is 2 weeks old. I started out breastfeeding but ended up having to supplement with formula due to weight loss. The hospital gave us Gerber Good Start Gentle Pro. It seemed to work well with her stomach. But then I had switched over to pumping & bottle feeding. That completely wrecked her stomach. She was so fussy & uncomfortable. 😭 So my fiancé & I decided to go back to formula feeding with the same formula. My daughter’s pediatrician recommended that we feed more regularly or a larger amount to be at the weight the pediatrician liked. So I started giving her 2.5 ounces & this morning her tummy hurt again. I feel so bad for making my little girl go through this. Does anybody have recommendations on formula for sensitive stomachs/products they use with their little one.