How can I tell if I have hypoglycemia?

Define. Hi. Please define hypoglycemia. If you're not taking diabetes drugs, true pathological hypoglycemia is vanishingly rare. Did you become confused, lose consciousness, have a seizure? If not, there is a popular self-diagnosis of "hypoglycemia" that isn't real. There are rare syndromes where tumors or other conditions can cause hypoglycemia; bet you don't have one. See an endocrinologist if indicated.
Blood Test. This is best evaluated by lab-work or a finger stick glucometer. It is also good to note the hypoglycemia's relationship to other events such as eating, exercise, or the time of the day.