Sudden onset of insomnia?

I am a 23 year old woman... physically active, with no health problems. I have never ever had a sleep problem, and just recently in the last 2-3 weeks i've had a terrible time getting to sleep. I don't feel as if I have an anxiety problem, and I have tried Melatonin supplements and Valerian root with no results. I don't want to see a doctor because I don't want to be put on a narcotic sleep med that's going to leave me in a fog, but I'm running out of choices (I'm in school and have an infant daughter, so being able to focus is important). Please help! Any suggestions appreciated.