One thing you should do ASAP is start taking at least 1,000 mg of Vitamin D every day, especially if you're spending a lot of time indoors. Extremely fast weight loss almost always causes certain vitamin deficiencies. If your Vitamin D gets too low, it will give you excruciating leg pain. Once your levels get low enough to cause the pain, it takes several months of supplementation to get rid of the pain and cure the deficiency. Other vitamin and mineral deficiencies can cause skin problems and even hair loss. I've never done meth, but have experienced extreme weight loss from some virulent illnesses, so I've been down that road. Start taking a good multi vitamin daily too, so things don't reach critical mass for you. And do it right away, too. Don't wait. Just MHO.