An abnormally low level of blood sugar, or hypoglycemia, is a sign of diabetes, according to Mayo Clinic. Hypoglyecmia can occur when a diabetic person takes too much insulin, engages in very strenuous activity, or skips a meal.
Diabetics who experience symptoms of hypoglycemia should take glucose tablets to raise their blood sugar, according to Mayo Clinic. Symptoms of hypoglycemia include shakiness and dizziness. The person may have an intense hunger and suffer personality changes such as irritability and anxiety. He may sweat and have a headache. If the hypoglycemia happens at night, the bed sheets may be damp from perspiration, and the person may suffer from nightmares or be foggy and irritable when he wakes up.