Hypoglycemia is when your body doesn't have enough sugar to help it work properly. You know how you need gas in your toy car to make it move? Well, your body needs sugar (or glucose) to keep it going too. When you don't have enough sugar, your body can feel funny and you might start feeling things like shaky, dizzy, or grumpy.
Sometimes, when you eat too much candy or sugary foods, your body gets too much sugar. But other times, if you go too long without eating, if you are sick, or if you have a medical condition, your body can have too little sugar. Hypoglycemia can be dangerous if it's not treated because your brain needs sugar to work properly.
So, if you ever feel weird and you think you might have hypoglycemia, tell a grown-up so they can help you get some sugar (like a juice box or a piece of fruit) to make you feel better.