People often report brain fog, tiredness and feeling sick when first starting a very low-carb diet. This is termed the "low carb flu" or "keto flu." However, long-term ketogenic dieters often report increased focus and energy. Many people report decreased hunger while following a ketogenic diet.
Instead, start by reducing your eating window by eating breakfast later or snacking earlier. In keto, you are encouraged to eat the same number of calories during this time but will still be burning fat in ketosis. Traditional protein shakes do not have the right MCTs or fat profiles to get you into ketosis and have far too many fillers, carbs, and protein. You should continue to decrease in increments of 5 net gram carbs per day until you start to see the transitional symptoms of ketosis.
A note about hypoglycemia - it happened a few times to me early on, but now even if I am as low as 2.5 I will not have any symptoms or go hypo. Something interesting happens when you are keto-adapted which prevents you from going hypo. Check this out for yourself, there are others who fast or are keto and regularly have what would be considered extremely low blood sugar without any issues. Ask your endo or doctor if you like but chances are, like mine, they will tell you you will still go hypo and not have the symptoms. To which I said I have a 150IQ, so please stop talking down to me and insulting my intelligence.