I went through a similar elimination diet a few years ago. Bob's Red Mill makes a really good gluten-free hot cereal. You can order it on-line if you can't find it locally. And since you can't have soy, try nut milks. Many are sweetened with sugar so look for the unsweetened variety. Again, these can be ordered on-line if you can't find them in your grocery store. Amazon carries it.
And hang in there -- once you get used to it, it's not so bad. The hardest part for me was eating in restaurants. Throw yourself on the mercy of the server and tell him/her you have food allergies (even though you aren't allergic, most people don't understand "sensitivities"). Most restaurants will work with you.