Girls might see and feel a white, mucousy discharge from the vagina. This doesn't mean anything is wrong, it is just another sign of your changing body and hormones. This is when the penis becomes erect when a guy is sleeping, and he ejaculates. When a guy ejaculates, semen comes out of the penis - semen is a fluid that contains sperm. That's why they're called wet dreams - they happen when you're sleeping and your underwear of the bed might be a little wet when you wake up.
Wet dreams become less frequent as guys progress through puberty, and they eventually stop.
Just as those hormones create changes in the way your body looks on the outside, they also create changes on the inside. During puberty, you might feel confused or have strong emotions that you've never experienced before. You might feel overly sensitive, or become easily upset. Some teens lose their tempers more than usual and get angry at their friends or families. You may feel anxious about how your changing body looks.