formula suggestions??

I'm calling in a pediatric appointment but I'd also like to see what other moms think while we wait. my 6 week old hasn't reacted well to any of the formulas I've tried. we started on gerber good start with iron but she was extremely gassy and colicky so we tried enfamil nutramigen and that one had her with constant diarrhea. her pediatrician suggested soy, so now we're on enfamil prosobee but now she's spitting up half her bottle after every feed and her reflux is worse. I'm not sure what else to try. 😰