michelle,
have you found out what your baby is allergic to? eg. if its whey protein in cow milk, which my son is allergic to.. you have to avoid alot of products. most breads, confectionary, cheese, most margarines, cake, butter, even sweets. can only eat Gerber rice cereals. most other cereals will have milk or whey protein.
several people have asked about soy milk formula.. and you have said you tried. unfortunately, some of the soy milk do have whey protein or some other protein that your baby may be allergic to.
you will need to avoid any food with the same ingredient. even donated breast milk.. if the mother drinks cow milk, you might get some of the things your baby is allergic to in the donated breast milk.
please please find out exactly what your baby is allergic to. you might be able to switch to formula