Stephanie,
I am sorry to hear you had such a hard time with your son.  Sometimes what
happens with babies that have multiple food allergies is that they react to
what their mother is eating.  The only answer is a very strict elimination
diet to determine which food is causing the problem.  I know of a mom who
could eat hardly anything, her baby was allergic to wheat, dairy, eggs, corn,
chicken, beef, etc...  It was very hard on her but eventually her baby was
able to tolerate her eating more and more of the foods.
I am glad the soy formula worked for you.  Best wishes!
Kim