so confused when daughter latched

anna

I am so confused and exhausted . I normally pump (not much) and supplement with formula but upon taking advise from y'all I decided to let my daughter start latching on to try and avoid formula. well it had been 5 hours since she ate and she woke up to eat. It had been 4 hours since I pumped so I know i was full. she drank from the left boob for 10 min and burped and than the right boob she drank for 6 min and than she refused anymore she was done and went back to sleep. I could hear her gulping like she was drinking so I guess that good but I feel there is no way she got all she needed from 17 min of nursing I see some of u all nurse over an hour. I don't understand. this is why I felt more comfortable pumping so I know how much she got but pumping is getting to me and I am overly exhausted getting up every 3 hours to pump. help.. 😣