Since you know how you feel when you eat your regular diet and you know how you feel when you fast, you're in good shape. What I mean is you could do some sort of very limited diet that eliminates your symptoms, i.e., a very low reactive diet. Then when you're stable, start testing new foods. You could check out Lyn-Genet's Plan.
Another possibility is to do Protocol 1 for Miracle-Mineral-Supplement and see if you can clean yourself out enough to eliminate the allergies.