Please reply me a few questions then I can suggest something for you.
1) Is it this problem of sleep is since your child hood?
2) Do you feel any bad effect due to less sleep?
3) Do you sleep in the day time?
4) Did you go to doctor for this problem ever?
5) You cannot sleep b/c of fear of darkness or only being alone .
What you can do now that pray 5times & read Quran daily with translation.
Read sura Falaq & sura Wannas before you go to bed.
I will wait for your reply.