5 1/2 week baby up all night & wouldn’t eat.

Went to bed at 11:30 last night fed babe for 15mins he wouldn’t go to sleep so I let him lay awake for a while before trying to get him down, well 2 hours pass & he’s still up & cranky now he wouldn’t eat, this continued until 5:30 am got him on boobs for 10mins and finally went to sleep. so now he’s been sleeping ever since. He usually eats every 2 hours sometimes sooner, I’ve tried to feed him and he’ll only eat 1-2mins before he’s done & deeply sleeping again

What are we dealing with here, pls tell me this is growth spurt behavior. I really

don’t want this to mess up my milk supply.