Cluster feeding HELP

Ladies help! My little girl is 3 weeks and has been cluster feeding like crazy the last few nights from about 6/7pm to almost midnight! It’s making me go insane especially because at some point I’m pretty sure she empties me out and begins to get upset and restless wanting more. We then try formula and she refuses to take it. I’m beyond frustrated with this especially because it seems I’m not producing nearly enough for these cluster feeding sessions. Not to mention how extremely exhausting it is to feed for that long. My back hurts, I’m extremely hungry and tired afterwards and my SO is asleep by the time we’re done, so he can’t help much. It’s the hardest part of our day. How long does this last and what can I do to help her?