You're pretty normal, I'd say. I did Atkins for 10 months and then switched to CALP and for the first week I had a headache that seemed to get worse by the day just from putting carbs back in my system. But after that, I was fine and have even started losing on the CALP and I'm able to eat carbs... It's all in the timing on the CAD/CALP programs, and it seems to be working for me where Atkins wasn't.