If you're getting episodes within a short period of when you eat, you could have what's called "reactive hypoglycemia". This means that when you eat certain foods, your blood glucose spikes, then suddenly the bottom drops out and it's too low (hypoglycemia). If you aren't careful, it ends up being a vicious circle, because the glucose drops you eat something to raise it, but many people raise it too quickly again, which again causes it to plummet - and so it goes...