Fussy baby @ 4 weeks

Does anyone else have a fussy 4 week old? He was ok up until yesterday, and it's like a swtich flipped in the evening and he got really fussy and clingy. He sometimes rejects feeds which is very unusual. He screams when I put him down, he's restless when I hold him. I've changed his nappy, checked temperature, tried massaging belly, clothed appropriately. When my daughter was fussy, it was because of gas - nothing a massage wouldn't resolve, but he doesn't seem gassy - just needy lol

It's stressing me out knowing the poor thing is in distress 😥

P.s. is it possible that I overfeed him?! He's got a big appetite and I never limit his intake. He can drink up to 5oz a feeding (no force) - my daughter used to only manage 3oz at that stage. I give him 2 bottles of expressed milk a day, and breastfeed the rest of the time.