give yourself time! also - eat LOADs of whole grains and veggies - my motto is "Grains, Greens, & Beans" (and i just lump nuts and legumes in with beans... :)
also - a lot of people miss fat and amino acids when they first start to make the transition, so use a little extra oil and Braggs Amino Acids to help you get through the transition.
if you're struggling, there's no reason to rush yourself...just listen to your body, and you may find out that what you thought was a craving for chicken is actually a craving
b3 or
selenium...i use this site all the time to help sort out patterns in my cravings - then i can satisfy them way better than before...i'm definitely about a thousand times more nourished on this diet than ever before.