I sneaked a peek at your profile, and see that you've been on Atkins since March. Congrats on the lbs. lost so far!
Are you taking any kind of vitamin & mineral supplements? It would be a good idea to do that. No need to buy Atkins special brand, although they are fine ... but any good quality brand you can buy at a pharmacy are great.
Fatigue and lack of energy at the beginning of Induction would be due to your body de-carbing itself, and switching to ketosis mode. But by now, you should be at OWL level, so this isn't the likely culprit. Most common cause of fatigue and headaches for lowcarbers is low POTAASSIUM levels. You can take it as a supplement, or easiest way is to buy a salt-substitute product such as NoSalt or HalfSalt ... they contain potassium .. obviously one is half 'n' half with regular salt. You just sprinkle it on your food like regular salt. You need to replace your potassium stores every day, since it's washed out in the urine, and being in ketosis and fat-burning will cause you to lose more urine than usual.
Leg cramps are often caused by lack of calciium mostly, but also magnesium. Take a good quality Cal-Mag supplement ... pre-menopause you need 1000 mg per day of calcium, post-menopause that goes up to 1500 mg per day. You're likely getting SOME in your diet, but a supplement is a good idea. Make sure it contains magnesium in a 2:1 ratio (ie, twice as much Cal as Mag). Take the last dose of the day at bedtime, for relaxed muscles.
Hope this helps. I see your location is ca. Is that Canada, or California?? Just being nosey ..
Look forward to more posts from you
Doreen