Taking pills is not the answer. There are better ways. Learn about in-bed relaxation methods, such as deep breathing and progressive muscle relaxation. There's also a complete suite of drug-free methods known as CBT sleep training programs if you need more help.
Hey, sorry you are having this issue. Sometimes a little more physical activity/exercise (done intentionally, not just the walking done on college campus) can make us sleepier. Try not to turn to drugs but you *could* occasionally try something like Tylenol pm or ibuprofen pm. Are you stressed? Are you laying and worrying? That may be handled by some de stressing techniques. Let me know if you need ideas for that.
The first is to try a supplement called L-Theanine, relaxes the mind without sedation, even good for daytime use unlike melatonin that makes me feel. Sick.
Second suggestion. If you have a phone and youtube access, with earbuds, search for programs including, binaural sleep hypnosis. There are many many for different time durations and with small enough buds I can fall to sleep quickly laying on my side.