def sounds like reflux to me. my little one started all this jiggling around during feeds, refusing the bottle, crying, screaming through feeds etc at 6 weeks, so you are at 7 weeks now, it could be reflux. apparently the babies try to drink to ease the discomfort but then overeat. my DS now is on Zantac and i saw the improvement within one or two feeds. i would advise you see your paed asap, as when i went to mine i thought i was just a overprotective mum making a fuss about nothing and the paed said i did the right thing to go in and see him as reflux is very painful for the babies.
good luck