Troubles sleeping

This is not good, I am staying up later all the time. It is getting closer to the end of my second semester and there seems to be an abundance of work to do.
Anyone have suggestions for sleeping without the use of medication? I didn't realize how much my lack of sleep plays havoc with the body. I am lashing out at people with no real reason. I don't know maybe I am losing my mind.
Ok so I really need to get some sleep so I am going to stop here.......wish me luck!