G.T.
My daughter was breastfeeding. But, during her 2 first weeks, she had to stay at the hospital and I was pumping. I had to pump like crazy to keep up. Fortunately, I was producing a lot!
The nurses couldn't believe the amount they were giving her in her bottles, close to what you mention.
But, she was a big baby (nearly 10 pounds at birth).
As long as your baby doesn't seem to suffer (gas or tummy ache) and is gaining weight in the normal range, I would't worry.