Reactive hypoglycemia will also cause the same symptoms you describe .. especially since you experience this after eating.
When you eat, it triggers the release of insulin to deal with any carbs that may be present. For sensitive individuals, even though the carb intake may be low, the hormonal response to eating is the same as if a larger amount had been eaten. The excess insulin will cause what little sugar there is to be moved into the cells, thus making the blood sugar very, very low. And at the same time, there's still extra insulin floating around. The symptoms .. extreme fatigue, tiredness, sleepiness, nausea, headache, chills .. some people even throw up, or faint. Some people even have the same reaction to zero-carb foods with artificial sweeteners, since the sweet taste triggers the insulin release.
I don't have Dr. A's newest book, but I know he devoted an entire chapter to hypoglycemia, insulin and diabetes in his other volumes. It's such an important issue, so I'm sure there's discussion of it in the latest edition.
In general, to relieve the symptoms of hypoglycemia ... eat smaller meals more frequently. This will help to avoid the big surges of insulin, and long stretches between meals where the blood sugar can drop too low. As well, never eat carbs, or fake carbs alone. Always have some protein or fat with it, to slow the absorption and thus again, prevent a spike of insulin. And preferably, avoid all sweets completely, including artificial sweeteners, since they can trigger insulin just the same as real sugar.
Do have things checked by the dr. though. Hope you feel better soon
Doreen