breastfeeding help

i don’t know what to do.

my LO is almost 8 weeks. i’ve been BF since the beginning, had to supplement in the hospital while my milk was coming in. then ended up supplementing due to poor weight gain. stopped the formula due to constipation. we went in to see a lactation nurse today, and after being on the boob for 20 minutes, he ate half an ounce.. moved over to the other side, and had 1.5 oz. he’s always taken a half hour-45 minutes to eat.

i feel like i’ve gotten to the point that the best option is to stop breastfeeding, and to give him expressed milk. i feel like i’m being selfish in this decision, because i was hoping we would have a longer actual breastfeeding journey.

looking for advice. 😭