N.B.
My baby did the same exact thing from 2-4 months of age. In the afternoon & evening she would fuss after 1-2 ounces. It didn't matter if it was breast or bottle (breast milk). My daughter's problem was acid reflux. She didn't show the common signs, she didn't spit up much. I realized it when she choked one night in her sleep after eating. I just had to have lots of patience--I would feed a couple of ounces and then let her have her pacifier for awhile before trying to feed again. That seemed to work. She just ate often. I also kept her upright for 20-30 minutes after eating. I ended up pumping and giving her bottles since I was feeding her all of the time. I have a really good milk supply and didn't notice a change in my supply. However, her doctor did tell me that exclusive pumping can cause a decrease--but not for me.