Can docs explain what does low blood glucose mean?

Hypoglycemia. Low blood sugar=hypoglycemia. The first symptom is usually hunger, then dizziness, sweating, and palpitations.
Rare disorder. Symptoms include nervousness, sweating, hunger, anxiety, blurred vision, fatigue, fast heart rate, etc. -- however unless you have diabetes and are on Insulin or other medication, have renal or liver disease, cancer or prior stomach surgery -- then true hypoglycemia neveer occurs in human beings. If it a very frequently and incorrectly made diagnosis.