Eating long enough?

My week old daughter usually feeds on one breast per feeding and finishes that breast in about 8-10 minutes. When she finishes she will pop off and be completely satisfied and “milk drunk”. I try to burp her and get her to eat more but she is never interested and just wants to sleep.

Is she getting enough? I’m pretty sure she is draining the breast but everyone talks about how they should feed on both sides every feeding. I use a hakka on whatever side she doesn’t drink from and will collect anywhere from 2.5-4 ounces every time. Does that mean she is drinking that much when she empties the other breast?