What is it about 1-5am??

Em

Ok, so my 3 week old is waking every hour to feed at night (or just fussy from gas then wants to feed for comfort) from 1-5am. I would consider it cluster feeding, but this has been going on for a week! He gives me 3 hour stretches (is that even considered a stretch haha) from 7-10 and 10-1, but after that I can pretty much throw the idea of sleep out the window. Anyone else experience this? He’s my second baby—our first was a great sleeper until 3 months.