Chronic Gastrointritis

I have been diagnosed with chronic gastrointritis. I've had numerous symptoms for 17 years now. Diarrhea, gas, joint pain, low grade fever, chills and headache. For the past year though, I've begun suffering constant nausea which causes occasional vomiting and violent diarrhea. Further to this, the onset of my period now causes me to be horribly ill and I've begun developing allergies such as an allergy to wine (any wine) and to antibiotics (which I've never previously had). The allergies all present the same symptoms severe vomiting and diarrhea with chills and fever and some hives and low blood pressure. I've had every test possible and everything comes back fine. My doctor is perplexed and it has gotten to the point that the list of items I can eat without consequence is small. The amount of food I can eat at a time is small as well. I would love suggestions.