Night breastfeeding

My babe is 3 weeks old. We did fine at night up until maybe almost a week ago. We are struggling now. It seems like the first night time wake up, she cluster feeds. For hours. She doesnt do it during the day.. I find if I have some pumped milk shes fine if I give her the bottle. Although weve only done that twice in the last week. Weve been up for 2 hours. She lays down for enough time for me to just start falling asleep and then wants to eat again. Idk what to doooooo.