Formula reaction

Sounds like shes going through her growth spurt and is cluster feeding to tell your body how much milk she needs. You can add formula but you risk decreasing your milk supply and needing to supplement more down the line unless you keep up with pumping during her formula feeds.

I combi feed and it's amazing! My husband takes the first feed of the day so that I can go back to bed and recover from the night. It also allows my son to take a bottle from other relatives which has allowed my husband and I to go on dates. Finally I prefer formula over pumping since it frees up time, is easier to store, and I can easily travel with it.