I used to have that trouble when I was 13 too. My mom took me to the doctor and he questioned me about stuff. Then we talked about my erections at night and having to pee and dreaming. Like I would dream I needed to pee and had to go so bad in my dream I would just go and pee someplace. sometimes I would dream of touching a girl and then stuff would come out in my pants. Sometimes I would just pee the bed though. It stopped when I was 14 and knew about some of that stuff then. It will get better if you dont worry.