FEEHD, or fasting-evoked en-route hypoglycemia in diabetes, can be dangerous. When your blood sugar drops, you may develop symptoms such as feeling shaky, hungry, or hot. Your vision may become blurred. You can become lightheaded or confused. You may feel dizzy, faint, or even pass out and become unresponsive. These FEEHD symptoms can make walking and driving to and from your test dangerous…or even fatal.