Bikini, I felt rotten a lot during the first month. I think it takes longer for some of our bodies to switch over to a ketone based metabolism. Sometimes I would feel really good, then would have more bad days before the good ones returned.
I would read the posts about people feeling good and having energy, and I seriously wondered several times whether or not I would be able to stay on Atkins.
But I kept going, and all of those bad times are in the past now. I honestly feel better than I have in many years... so many wonderful health benefits.
Give yourself some time for your body to adapt. It will.