Hypoglycemia can cause you to feel and/or be shaky, This would typically happen if you went too long without
eating. There is a condition known as hyperinsulinemia
that can cause hypoglycemia. Basically, you eat something containing carbs, your body overreacts with the amount of insulin it sends, and when your body finally starts using the insulin properly, you have too much of it there and you end up with low blood sugar levels.
There are other conditions that can cause your symptoms.