Why I always fell asleep on my desk in class

When I was a kid, I never got a good night’s sleep. I was always tired. I would fall asleep on my desk in class. I would constantly get yelled at by my teachers to wake up and pay attention or focus on the lesson or just wake up and stop sleeping in class. Sometimes I would sleep during lunch and in the hallways at recess. Other kids were playing and havin fun and I was trying to sleep. My elementary school teachers thought I was overwhelmed by the lesson because of my learning disability and would fall asleep. No one ever asked me about my quality of sleep at night. They all thought they know what was going on with me. According to the adults around me what was wrong with me was the same thing that was wrong with all foster kids. Foster kids are just damaged and have problems. The solution was always to give the poor saintly foster parents more support.
What they did not know is that there was a reason I was so sleepy all of the time. My father was a pedo. Bed time was super anxiety provoking for me. My mother would try to catch him in the act and would come barreling down the hallway and come into my room and say “What are you doing in here”? He would move away from my bed over to the window and say “I thought I heard something outside”. She would go back to bed. Depending on how angry she looked he would either go with her or not. I was always afraid of what would happen if she actually caught something happening. It took me years to realize that would never happen because it was not like she was tip toeing in the hallway. To feel safe, I would sleep under 8 or 10 blankets and sometimes I would empty all of my clothes out of my drawers on top of all of those blankets too. I would be so hot and sweating but I felt safe because I could not be seen underneath all of that. I think I was 30 years old before I could sleep without sweating. 
This even affected how I dress. I would always have on way too many clothes. Layer upon layer of clothes. I would tell people that I am always cold when they would ask why do I have on three pairs of pants, four shirts, a sweater, and a jacket. Even as an adult I know if I am so layered up that I am sweating I need to get still and think about why I don't feel safe. Sometimes it would happen without me even realizing it. I would just be sweating and needing to take off layers. I am 44 years old and still can catch myself wearing way too many clothes trying to retrace my steps to figure out where the trigger happened. At least now I have more awareness. That's something. That's progress.