Welcome to DC.
I followed the Keto diet for a couple of years. It worked great for me, but it was also very hard for me to keep following. I did not fast though.
A few questions that I have: Are you getting enough fats in? What are your daily macros? For me, my macros were 75-80% fat, 15-20% protein, about 5% carbs. I would start my day with a fat bomb and bulletproof coffee. Then my numbers would look great all day.
A little bit Ginger. A little bit Mary Ann.