Usually, hypoglycemia can be detected by its symptoms that start to appear when glucose levels are 70 mg/dl or lower. And they include:
Hunger: especially a very strong cravings for sugars and carbs.
Sweating: this type of sweating is different from the regular sweat experienced normally after exercising or embarrassing situations. This one is cold sweats that usually feels like the energy you have left is being expelled from the body with these small droplets.
Sleepiness: this symptom freaks us all out when we experience hypoglycemia during sleep, so you start to wonder if you're really sleepy or if you are experiencing a hypoglycemia.
Fast and Irregular heartbeat: as your body is trying to compensate the insufficient amount of fuel.
Fatigue: overall feeling of tiredness or exhaustion.
Unusual behavior, slurred speech or clumsiness: you feel like being drunk (and this leaves some funny memories). This happens mainly due to insufficient supply of glucose to the brain cells.