I glad to hear that things are okay at home. Sounds like your parents are having a hard time understanding what is happening or that they dont know how to respond. So I suggest going to a teacher that you can trust. In highschool I found that I made some great relationships with my teachers to the point they gave me extra support in their lunchtimes. If you do have a teacher that you really connect with, it may be a good idea to have a private talk with them .
Ah procrastination, I have a essay due next week! I have not started it, I dont feel like doing it but I know that I have to or else I will fail! If school isn't for you, have you considered looking for an apprenticeship or traineeships?
Petal's suggestion about writing a little to your parents is an excellent idea too. What you can try is switching off all distractions, and sit infront of your studies. It can help you get into the zone. I put on some study instrumental music, this has helped me focus. The music is really soothing. I use this method for exam study too.
As for sleeping, try some music. I found this helped me alot. You tube has alot of sleep music. When im restless, I elevate my legs on a pillow, helps me to relax and with blood flow. There is a condition called restless legs syndrome, you could ask your doctor about if this is what you are experiencing. Sometimes even a panadol can help calm my restless arms and legs.
Keep in touch okay, let us all know how you are doing.