Have you tried Dr. Jay Gordon's method for night weaning. Some mothers here say it works really well.
Oh when you said you want to eat pizza, I wanted to say there is a great pizza which is free of all the things your LO is allergic too, healthy and high-calorie at the same time. I don't know if you can find them where you live but they are great:
Amy's Non-Dairy Rice Crust Cheeze Pizza
Amy's Roasted Vegetable Pizza