My DD had a growth spurt at 3 weeks, she was feeding almost all day for about 3 days before settling down again, it's to increase your milk supply. It is exhausting though! Eat and drink plenty and try to feed lying down so you can rest.
He's probably just building up your supply. It should even out by about 6 weeks.
It's worth getting done RL help to check his latch though because inefficient feeding may result in needing to feed more frequently. Is he actually getting milk? Can you hear the suck-suck-swallow rhythm?
Will he settle just for physical contact from you/your partner? Perhaps in a sling?
Help! My baby is 3 weeks old and is bf. the first 2 weeks were great and he fed well every 3-4 hours. Now he is constantly rooting and demanding to be on the breast all the time. He doesn't take much and just falls asleep on the boob. The wakes up with avengance 20-30 mins later and it starts all over again. Any advice?!?