Doxylamine
"I am 24 years old, I had to stay awake during the nights of the last week due to a university exam. four days after the exam is finished i can not sleep well because my bed time has changed. and i feel so tired during the day. last night at 2:45 am I took one (50 mg) Tab and after 30 - 40 min i slept deeply. At 9:00 am (after 6 hours) I woke up feeling little bit heavy and sleepy, so I went beck to sleep for another 2 hours. After that I woke up feeling fresh and energetic like if i had a good continous sleep through the night."