Please Advise. Losing My Mind.

Is cluster feeding a thing? If so, how does it work? My daughter is 3 weeks old and I feel like all she wants to do is be on the tit. I know she’s getting milk because I can hear it and after eating for 30 minutes straight I feel like she just cannot possibly still be hungry. But I burp her for a few minutes and she’s right back to rooting around and waving her arms and legs like a mad woman who hasn’t eaten in years. She has been doing this alllllllllll day for the last 2 days and I just don’t know what to do. Is she really still hungry? Please leave your experience in the comments because I feel like I’m losing it.