Some people have better luck doing drastic changes, while others are more successful doing gradual change.
Four weeks is pretty good. Let's say that for your whole first year of trying to change, every four weeks you just caved and had pizza or a sandwich, or whatever wheaty thing it is you miss. That's 13 servings in a year. Contrast that to someone eating a SAD diet who may be having 365 wheat servings/year - because after all, they can't live without that cereal every morning or that sprouted wheat tofu sandwich at lunch.
Even if you continued for the rest of your life to have 13 wheat/grain days a year, you'd be so much better off than people who think "grain is life."
"Right is right, even if no one is doing it; wrong is wrong, even if everyone is doing it." - St. Augustine