Help! Newborn won't sleep/eating constantly

My newborn is only 5 days old and at night I can't seem to get him to sleep at all and it's driving me crazy. He'll only stay asleep in his bassinet for an hour at most and then when he's awake, which is hours at a time and when he's awake he's constantly feeding. I'll feed him from my breast from 15 minutes, 30 minutes, or switching breasts for an hour to an hour and a half and somehow that still isn't enough for him so I'll also feed him what I pumped (I've been pumping a little here and there because I'm engorged to get some relief and I also pump when I supplement so my milk supply stays up) and also end up having to give him formula because he will not stop crying until I do. Does he really need to feed this much?? I've tried giving him a pacifier to see if it's just him wanting to suck but he just spits it out and cries for what I assume is for food because he's suckling the air and his hands. Is there any advice anyone can give me? It's really stressing me out. I probably only get a total of four hours of sleep a night because of it. He'll stay up for hours on end too. I'll feed him, think he's full, and he'll be good in his bassinet for like ten minutes and the whole feeding process starts again.