k7maker,
if it helps , don't cut cold turkey from 500g carbs to 20g in 1 day.. give yourself some time - say 4-5 days to go down. While i don't know how much carbs i have been eating before, while i was reading Dr Atkins New Diet Rev. book, i was slowly cutting down and when i finally finished the book - i went on the 20g carb. The first two weeks are the hardest in my opinion, so plan it, what to eat, what not to eat, when to start etc.. keeping a log helps very much.