Is Nutramigen good for gy fussy babies?

I have a 5 week old son and we've been through pretty much every formula. He has gas soooo bad that not just while awake he grunts, he does so all through his sleep. At night time when his bowel movement pes he fights and fusses with it sometimes takes him hours to get it out. It's a lose stool so I'm not understanding why he has such a hard time? We tried Soy and it made his stool way too hard for a baby so we switched to Nestle good start and that was good for about 5 days, he stopped fussing for a few days but the gas never went away. The past 2 nights he has cried for hours at night and has started to eat less. We tried Mylicon drops they do absolutely nothing for him. And the doc said to stay away from Gripe water that it has a very little amount of sedative in it. Have any of you used Nutramigen for fussy, gy, hiccup baby?