I Have Constant Nausea. After Eating Even A Small Amount

I have constant nausea. After eating even a small amount it increases and is then accompanied with heart burn and abdominal pain, bloating, often flushed face and gas. I have removed all gluten from my diet nearly two years ago with improvement until about 3 months ago. Then chronic heartburn started along with the above symptoms. About a month ago it was suggested by a doctor that I had food allergies and to remove dairy and soy from my diet. That helped for a bit but no matter what or how much I eat within a few hours I am miserable. I am still eating gluten, dairy, and soy free but still sick daily.
Any direction would be appreciated.
Thank you Denise