You need more fat than you are eating. Your body is trying to store for a reason. As a vegan, you need protein. Try a protein shake.
I believe you have celiac disease. Get tested for it. It's way more than bread. It's gluten. Soy sauce, rice, barley, wheat, and sugars all make celiac suffered miserable.
Go to an Ayurvedic medicine practitioner. They specialize in diets as treatment.