My fourth month old was nursing fine until yesterday. He will latch and drink but when the flow slows down he gets aggravated and pulls off and screams. I switch him to the other breast and he drinks again until it slows down then screams. I try to put him back on the first breast but he cries and thrashes. He has been getting bottles while I work (2 bottles three days a week) but the flow in newborn so he doesn't develop a preference. After nursing he'll want to nurse again about an hour later which is fine but by that time he's so sleepy he only sucks a few mins. I'm hoping this is just a phase. I've read about the "four month fussies" any advice?