I'm hypoglycemic but get three regular meals. Do I still need to snack?

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 never occurs in human beings. If it a very frequently and incorrectly made diagnosis.
hypo's preventable. If you are taking Insulin before meals, you need to consult your doctor. Infrequent episodes of low blood glucose may not be preventable given the varible conditions of eating and exercise, but recurrent hypoglycemia is preventable with adjustments of you management program.
Yes. If you have symptoms of hypoglycemia, the best way to prevent them is to eat regular small amounts, and don't go for a long period without eating. This can usually be accomplished with an late afternoon and a bedtime snack, along with your meals.