Talk to General Physician on Vomiting, Diarrhea, Nausea & Loose Motions

I am having loose motions from last 15 days. I went to doctor a week ago and he prescribed some medicines. After using them for three days I was normal but when I started Normal diet (Roti/Paratha) Loose motions came back. Now the condition is so severe that I have loose motion even I drink water. Rougly 12 loose motions per 24 hours. When I take small diet means Bread with milk or anything else I start feeling nausea and finally I vomit. Please guide me what to do now.