At my wits end! Please advise. FTM

Danielle
So my little guy will be 2 mons on Tuesday. We've been having so many issues with his eating since day one. When he was first born, he lost too much weight (8lbs 11oz at birth 7lbs 5oz at first check up at 2 weeks) So we got him back to his birth weight. Then he has had very very bad colic and acid reflux. We went to the doc friday and the nurse practitioner said he was over eating and that's why he was throwing up (due to me feeding on demand...oh so I thought) and had pretty much gained too much weight(8weeks at 12lbs 15oz). Colic drops are a joke when it comes to this. He is ebf. He gets bad gas whether he's on the boob or bottle (we're currently using Dr. Browns with the vent). And he spit up after EVERY feeding even with the prescription meds. His cries from the gas nearly bring me to tears and we have tried all types of gas relieving positions and he is still in pain on top of the reflux even after following more of a schedule and switching tonthe slower flowing noob more. I just don't know what to do. Any advice?