Tell your doctor that you can't seem to fall asleep many nights and it is effecting your life/work/school.
Go as far as to say that you have cut out caffiene and even tried taking diphenhydramine and doxalamine succinate but they didn't offer much help. If he/she asks about your levels of stress then comment that they are nothing out of the ordinary except when you are too groggy to perform your daily tasks.
Good luck.
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Have you ever been high? Have you ever been stoned? Have you sat on the long couch with a tingling in your feet, in your toes, and known what was coming? Have you ever been messy, sloppy, rolling? Have you ever taken acid, snorted coke, popped pills, dropped downers? Have you had your little break today? Have you been happy with your choices? Have you ever wanted never to come down? Have you... have you... have you?
Now, have you ever been to jail?
"I dislike the drug you are using, but I would defend with my life your right to use it."
- Paraphrase on Voltaire