First time mom!

I was talking to a physical therapist and I was telling her by Im just not pumping enough to feed my baby while I’m at work. And I feel like I’m starting to head towards needing formula but I told her im worried about ingredients. And she told me she made her own formula, her pediatrician sent her to a pediatrician dietician and they worked on a formula together. I was just wondering has anyone else done this? I’m going to speak with my pediatrician first, but just wanted to hear other mom experiences with it.