One night during grad school, I took a few Tylenol PM to try to get to sleep, and then every time I started to fall asleep, one of my legs would jerk and wake me back up. This ultimately left me even more exhausted and frustrated. Similarly, when I returned from Europe with a case of the German measles and a nasty cough that kept me up for 24 hours straight, I did what any normal person would do. I downed some Nyquil in order to knock my ass out so I could get some much needed rest. I then proceeded to wake myself up by coughing every 15 minutes and had wierd fever dreams in between.
I think what I'm saying is that my body is too strong for the sleep aid. Let's hope that the melatonin will work, or I will have to get serious and get a prescription for non-habit forming Ambien.