When i was little i used to wake up and cry, i don't do it anymore but what was it?

Childish fears, those are. Young people are usually afraid of the unknown, being alone and the barely visible; the dark, for instance, and can lead to sudden reflexes out of fear, like shouting or shivering. However, as you grow up, you get used to it and realize that night life is quite fine, because of your environment's influences, and you motivate yourself that there are actually no monsters under your bed. Hope this helps.