Is a sodium mag. test a 100% accurate test for a sodium deficiency?

Severe or extreme diets are NEVER a good idea, because they can drive down a lot of your body's essential nutrients and minerals. Severe diet combined with lots of water intake is a recipe for a sodium deficiency. But you may be having problems with more than just a sodium deficiency. Since your nutritional status was compromised for so long, it will probably take a little while to recover. If it were me, I'd include a good multivitamin, and eat a NORMAL balanced diet, to include red meat, some root veggies, and some fruits mixed in there. Salt your food, and take a multivitamin tablet twice a day. You SHOULD feel MUCH better after 2-3 weeks of that, but it MIGHT take a little longer. I wouldn't obsess on your Sodium level. I suspect your EVERYTHING level is down. If you go back to your doctor, ask him/her to run a Nutritional Panel on you. You might be surprised at what you're low on.