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Most of the symptoms you report are from not eating enough salt. Try to get between 10 and 15 grams (2-3 U.S. teaspoons) a day, for maximum health. This will also help your body retain potassium, magnesium, and calcium. Also, making sure to drink to thirst will help keep your electrolytes balanced. Don’t overdo the liquid, as overhydration can have serious ill effects.
The main characteristic of a well-formulated ketogenic diet is low carbohydrate intake. This is to keep insulin secretion low, thus preventing the metabolic damage caused by chronically elevated serum insulin. We want enough insulin, but not too much. Carbohydrate, being mostly chains of glucose molecules, strongly stimulates the secretion of insulin, which is why you want to keep your intake strictly limited.
Protein, while it stimulates insulin secretion to some degree, is required in the diet. We recommend a moderate amount, between 1.0 and 1.5 grams per kilogram of lean body mass a day. If you are trying to build muscle, eat at the higher end of the range. You could even go as high as 2.0 g/kg/day.
The remainder of your energy then must come from dietary fat. The good news is that fat has a negligible effect on insulin, so it is a safe source of calories. In a low-carbohydrate context, fat will satisfy hunger and still allow any excess body fat to be shed. We recommend eating to satiety, not to an arbitrary caloric level, so as to avoid the problems posed by over- and under-eating. When insulin is kept low, the hormonal mechanisms that regulate appetite are free to work properly, making hunger and satiety good signals for knowing when to eat and when to stop eating.
