Jennifer is absolutely correct-- with that particular list of things being avoided, any and all processed food is likely to be off the table, so to speak.
Soy and corn are ubiquitous in processed foods, and their derivatives are not always well-labeled (lecithins, starches, etc).
I'm just curious here, but why did your doc test for those allergens in particular? Had you noticed definite allergy symptoms when eating those things? Or was this because you were generally unwell? Depending on the severity of your symptoms, you might need to be carrying emergency medications to treat a life-threatening reaction; that's why I ask. It doesn't sound as though you have epinephrine. Is that true?
I'm assuming that you saw a board-certified allergist... but I'll ask because you mention "lists" and switching diets, indicating maybe... a rotation diet? That's not really the treatment for food allergy,
though it can be helpful with some intolerances. Please tell me that you were NOT diagnosed:
a) with testing alone, and/or
b) by a naturopathic practitioner,
c) via IgG/muscle resistance, etc.
The reason is that those are not
a way to determine whether or not you have an allergy
to any foods. As you've discovered, avoiding any one of the things on your list is difficult, to say the least (we have a soy allergy at my house, too, fwiw, and have avoided wheat as well when my DD was allergic as a toddler and preschooler). It can easily compromise your health to avoid a lot of foods without really great nutritional guidance! (That wouldn't be good either, and it's really hard work and a lot of stress. Nobody needs that unless they truly have to do this.)
If you're not feeling any better after a few weeks of elimination, I'd look beyond the current diagnosis and push for better answers from your doc.
Is there any chance that you might be a candidate for celiac testing? If so, avoiding wheat is probably the worst thing you can do right now, since you'll have to be eating gluten regularly for a reliable diagnosis.
In any event, we have several members who can definitely help with avoidance of all three of those foods.
I hope that you feel a LOT better soon.