So discouraged 😞

Ashley •
My baby is 3 weeks old. He fusses all day long and cries unless he is feeding. He's breastfed. Now even while feeding he's not happy. He grunts and crunches up his legs and cries. I don't know what to do anymore! I can't make him happy, I can't sit him down and even when I hold him he still cries. Anyone have any idea what could be wrong w him!?