Two things I have noticed.

First, are you getting enough calories? That could be the problem in losing weight if you are not getting enough calories. You can calculate your intake by using www.fitday.com and see if that is the case.

Secondly, I think your carb intake may be a little too low for you to feel well. I think everyone is different, but I would be having the same tired "can't work out" symptoms (plus some) at such a low carb rate. I realize Atkins does not require any carbs, but I couldn't get my carbs that low as you and be able to function, much less work out. Can you think about upping your carbs some to, say, 30g per day, and if it still doesn't help, to 50g per day? According to Protein Power, if you have only a few pounds to lose, 50g carbs per day is what is recommended.

Tomo