Big, big (((hugs)))
Elimination diets can be so frustrating
Especially since everything seems to have hidden ingredients - it's so hard to know what you're eating, especially when out, and what might be bothering your lo. Are you keeping a food journal? Might be the only thing that will help you pin some of this down.
Re: always starving, try to keep fresh fruit and veggies around. That was what kept me from starving when I was doing my dairy elimination. Just remember that the closer the food is to nature, the safer it is. There's no milk or soy or gluten in fresh fruits, veggies, rice, fresh meat, etc. It is hard when you have no time to cook, but if you have "grab and go" (apples, bananas, grapes, peeled/washed baby carrots, celery, cherry tomatoes, etc.) you have something to eat on the fly when you're hungry. Italian and Catalina salad dressing tend to be dairy free (though not sure about soy, tbh, as I never had to eliminate that) for salads or dipping veggies. Remember that you have to be eating enough (and resting enough!) to keep your supply up
Another "survival" thing for me was making big roasts, even though it was only DH and myself. Pork roasts, roast beef, entire chickens (or 4-6 breasts) - if I was taking the time to cook something for supper, I made enough for that night plus leftovers for at least one other meal, sometimes two. Fortified instant rice helped too - it wasn't really any work, and it had flavour when I made it with broth instead of water (you'd have to check for soy in commercial broths though!). One night would be pork roast w/ potatoes and carrots (a bit more work), the next night would be leftover roast w/ instant rice and corn (almost no work). It's definitely not easy, but we got into a bit of a routine and it helped so much.
It might be worth starting a new thread? Maybe about the difficulties you're having with the elimination and finding what foods are the triggers. I know lots of moms on the boards have had to do eliminations, and you're sure to get other great advice and tips to help you and your wee man.
Dropping off loads more (((hugs))) for you both. xxxx