This is pretty common. Somehow "low blood sugar" became an all-purpose explanation for any craving, lethargy, boredom, etc. It's not something we can self-diagnose by mood--true hypoglycemia involves urgent disorientation--more terror than fatigue.
Are you in the middle of major diet change? The first thing we deplete tends to be sodium, potassium, and water. Next up is protein, VitB, and VitC but those shouldn't exhaust more than once a day. Maybe try a pickle spear or cucumbers and salsa instead of a caloric snack and see what happens.
Lots of: urban hiking, cycling, sprinting
Lots of: fresh meat, seafood, eggs, organs, tubers, starchy fruits, low-energy plants, meat fat, dairy fat, oily fruits
Some: cured meat, dairy protein, sweet fruits, rice, peas, tree nuts, oily seeds
Minimal: soy, refined proteins, sugar, liquid carbohydrate, grains, beans, refined oils, peanuts