Hi and welcome to the community.
I am not that good with food allergies. You may want to check the food allergy community. You can find a link to it in the welcome message pinned to the top of the page.
One thought is that almond milk may be a good option for you. Soy milk upset my stomach, but I do well with almond milk.
If you have a nut allergy, you can try rice milk. There are many rice milk options available. Trader Joe's makes a really good one that they sell in the refrigerated section, if you live in an area where they are located.
It is not uncommon to have sensitivities or outright allergy to soy. Soy is one of the top 16 allergens.
You could start by maintaining a food diary to exactly know what type of foods precipitate your symptoms. If dairy products have been causing yours symptoms, then you could try and balance your diet with other carbohydrate, protein and fat rich food. You should include plenty of fresh fruits and vegetables in your diet. You could consult a nutritionist for a detailed food schedule. Warm regards.