Excess spit up and terrible eczema.

My son is 15 weeks old and has horrible eczema. I've tried everything to get it to clear up. He also spits up a TON. He's been on added rice starch formula and Zantac and he still spits up all day. I'm worried he's having a reaction to the milk based formula or something so I switched him to Nutramigen with some rice cereal today and he's still spitting up a ton. I know that he only been on it the one night, lol. But I can't help but be irritated and worried. He's gaining weight but his pediatrician is worried about what the spitting up is doing to his esophagus. I can't get it under control and I'm starting to wonder if the rash and the spitting up are related. Anyways, does anyone have advice or anything just to calm my nerves? Should I use soy formula instead? I'm just so sick of being worried about my baby constantly.