I guess you suspect Reactive Hypoglycemia.
If you have Reactive Hypoglycemia the weakness and lack of concentration if caused by low blood sugar while feeling hot, sweating and shaking is caused by the released of adrenalin to bring blood sugar up.
If you're at an initial phase you might experience these symptoms just three times a day. They're just annoying crashes. But if uncorrected they may become chronic and accompany you the whole day while the low blood sugar and adrenaling surge might develop into anxiety, panick attack, depression, phobias and more physical and mental problems.
Eating often is not the solution.
It helps because you're countereacting the effect of a low blood sugar reaction and this limits the adrenalin surge symptoms but if you don't correct the low blood sugar reaction you still will be suffring from unstable blood sugars and high insulin levels with all the consequences.
It's important to understand that low blood sugar is actualy fluctuating unstable blood sugar and according to endocrinologists like Dr. Berkowitz, they're just the other side of the same metabolic problem which is diabetes. Reactive Hypoglycemia is insulin resistance causing the pancreas to produce 10 times more insulin than needed. This is what causes the sugar crashes. Sugar crashes is what causes the adrenalin surge. Sugar spikes is what causes the insulin resistance. A whole graph of 24 hours would show roller coaster like graph of blood glucose. That's why hypoglycemia is a misnomer.
A first problem is your bowl of cereal. If you have RH your pancreas overeacts to concentrate carbs. Consider that even normal healthy people without an overeactive pancreas experience a sugar spike followed by a somewhat sugar crash when they eat concentrated sources of carbs.
Try to have eggs, veggies, salmon, nuts, avocado, cheese in the morning instead of the cereals and you should already feel better.
