Breastfeeding!

So I have a 6 week old baby & was in the nicu 4 days at birth so they automatically put the bottle but she does well latching! I breastfeed her but then she falls asleep in less that 10 minutes! I was giving her half formula & half breast! I have drank mother's milk tea & fenugreek pills & seems like I don't make enough so that's why I would substitute formula! Well today I wanted to try no formula and see how my baby does just trying to breastfeed and she gets a bit of me then she falls asleep but I been going at it non stop for 3 hours and she crys and crys she gets on the boob and seems to suck but like a comfort suck so I'm like baby you have to eat suck harder I just feel so guilty and want to give up. Does anyone have any recommendations! I'm so exhausted just trying to keep her to strictly boob but we are having a hard time I also have an amazing medela pump but I pumped and didn't even get an ounce from both! 😢 I even lay her on my chest just let her even play with my boob to stimulate but idk she's obviously starving if she's crying! Help before I give in to formula