Hi! I know this is such a difficult time. I remember all to well. We used Good Start formula. You need to wait a week or so before you will see changes. Did the problems begin with the new formula? If so, then maybe you need to switch back. From what I know Good Start is the easiest on babies tummies. So if you had gas problems before, they may get better with the change to Good Start.
The fussing while feeding: Leah was always a VERY fussy eater. I actually moved her routine around so she was getting her bottles before her naps becuase like you, she only ate well when calm and relaxed (nightime etc.) This helped us tremendously. EASY can have varatrions as long as you don't feed to sleep. So our EAS was ESAESA. I would turn the lights off in Leah's room, sit with her in the chair, feed her, then change her, then lay her down for her nap. Just a thought. My DD is also very spirited, so she needed to eat in a calm and relaxed place.
HTH, let us know how it is going.