You are most likely "carb sensitive", which means that those refined carbohydrates quickly turn into sugar in your body, and release a good dose of serotonin to the brain. This is a hormone that has a very calming effect and, for someone like yourself, will help to put you to sleep! Eating only complex carbs and shifting more into veggies, fish, and legumes can help with this problem. This will also help your blood sugar numbers come down.