I have only been low-carbing for about a week, with a good weightloss so far (about six pounds). But I have been feeling tired and, even more oddly, I'm experiencing musle tiredness/weakness.

Yesterday, my husband and I went out xcountry skiing. The snow was very deep, and we were having a difficult time busting trail the whole way. We were only out about 45 minutes, but I don't think I've ever been that tired in my entire life. ... Well, actually, now that I think of it, I know why this feels familiar. When I busted my femur a few years ago, I had a low hemoglobin count following surgery. I was so tired that even keeping my eyes open felt like a massive effort -- and I was close to feeling that way yesterday.

I'll admit that it was a tough ski, and my husband was baffed by it too. But I think I was a lot worse. We are regular skiers, so it's not like we weren't in condition for it. Something was different for me. I expected to be tired afterwards, but I was really zapped, like I never have been before in a similar situation. I'm still feeling shaky and weak today.

And, in general, since about the third day of this diet, I have been feeling tired, draggy, and a little muscle soreness.

I do take an iron supplement and a multi-vitamin. I am getting my full complement of carbs every day, plus ample servings of meat, eggs, butter, etc.

What am I doing wrong?