Horn, in the beginning stages I had the same thing. I would try to go to sleep...sometimes I would for a while, other times I would nod off for 10 or 20 mins and then jerk awake violently. It was really scary because I didn't know if it was going to stop!
I reasoned that it was my nervous system trying to deal with all of the poison in my body and mind. And I was right. After a couple of nights it was gone. Hang in their champ, it'll pass. What helped me was listening to some relaxing music at a low volume after drinking some nice warm tea (non-caffeinated!)
Let us know how it goes.