One of the reasons for that the pupils become bigger is that the light rays in the environment is too weak, so the pupils get larger so as to allow more light rays to come into the eyes. Maybe this is the reason for your pupils getting bigger when you woke up. It is normal, and you do not have to worry about it. But there is another reason for bigger pupils, that is, over-fatigue, high pressure, imbalanced diet, and so on. If so, you should pay attention to have a healthy and regular diet, and do not overuse your eyes without rest. Keep in a relaxed mood, do not get anxious. Eat more vegetables and fruits, as well as dairy products and fish.