Fasting and super grumpy

Hi- I went through your stop overeating class and it was great. I do pretty good at the fasting things, not so great at the flour and sugar thing. My question is I can feel myself get extra grumpy in the mornings, kind of unreasonable at times I feel. Is that because my body is adapting? Is it because I am still wanting sugar because I have not completely given it up yet? Or something else?
Thank you!