Can i add glucose with my protein shake if i have hypoglycemia? will it cause the sugar or insulin spikes and crashes that cause lightheadedness etc?

No and yes: The more important question is how do you know that you are having hypoglycemia? True blood test verified hypoglycemia is not normal. In a healthy person, simple carbohydrates during and immediately after vigorous exercise will be utilized by your muscles or used to replenish glycogen stores and shouldn't cause problems with exercise bouts exceeding 30-40 minutes.