I have same problem. I sometimes destract myself from the scary thoughts ex. i will use laptop or ipod until i FALL asleep. Another thing. Studies show if during your day you ask "is this a dream" on a daily basis in your dream you will say it and realise yes. Then you usually stop dreaming or wake up. hope this helps!
Try reading. Even if it sounds boring or if you don't like reading, at least try to find a book that interests you. Read it when you go to bed; it'll keep your mind busy and focused on the book so you "forget" to be afraid. Reading will make your eyes tired, so it'll be easier to fall asleep.