I have this with my nearly 4 week old ds. 
He's gaining well but I think he's signalling my boobs to make too much milk as he's not finishing the feeds. He gets quite fussy with the fast let down. I'll burp him and he'll go back on but not latch right or just fuss about. Some feeds he gets a good feed and I can tell the difference. But when he doesn't, he'll want to keep goin back on but not feed properly. Cluster feeding??
And after the short feeds He isn't a happy bunny, just arches his back, like he's not satisfied? He'll keep rooting but when I put him on he doesn't like it.
He's also has bouts of crying/roaring the past week is say. (Not from birth) he will do this on his back, after a feed for example. He burps well but his poo nappies haven't been big. More like skid marks each nappy?? But it sounds like a huge one each time!
My two girls were very easy babies, and trying not to compare but hearing his loud inconsolable (sometimes) cry is very different for us as it's something wee never had!
Also to mention he's got a stinking cold so all bunged up which doesn't help feeds.
Advice?!