Good luck - let us know how you get on. I hope it's not reflux for you guys.
The thing with reflux is that symptoms are so individual, some babies are really miserable all the time with it, my two weren't, they were both happy babies, DS wouldn't lie flat but DD has always slept well because she has always been elevated. She was very happy when we started a feed, took 1-2oz beautifully then that was it, no way was she taking more and then she would start arching and crying and just refuse.
Laura