Sleep

What is sleep? Can someone please explain to me what this beautiful concept of a 'good night's sleep' is? I feel like I sleep best during breaks because I sleep like, 13 hours a night. However, I am not a huge fan of sleep. I don't really like dreaming and nightmares tend to get caught in my mind; what I do like is the peace and restfulness you feel after a long rest. I don't really like sleeping because you're so vulnerable. I've never fallen off my bed, but I always have that feeling in my dreams like I'm going to fall off. I feel like I'm the only person in the world who doesn't like sleep. Am I?
Lately, I've been very tired. I don't know if it's because I'm a teenager or if I don't get enough sleep (probably both).  Being tired is hard on me. It makes me irritated and makes my head hurt. I don't like that. I wish there were more hours in the day so I could get all of my work done and still sleep well. It's so hard. How do people do it? Right now, I'm quite tired, but I'm still trying to go about my day. It's not fun.