I'm sure someone else has gone through this at one point or another...

This week actually went a little better, I was able to fall asleep all the majority of week days, although it was sort of fragmented, I usually managed to pull off 6 to 8 hours a day, I usually was asleep before midnight.

Last night went a little different for some reason, I didn't fall asleep until like 3 in the morning, although I did finally sleep for about six hours after that.

Anyways, I'm sure it's just all in my head or something.
When I don't sleep properly, I start stressing myself out because I feel like crap in my classes; my classes are math-heavy, so on any small mistake I do starts messing with my marks, and I also don't feel as energetic to be able to go out and work out like I'd like to.

Does anyone have any suggestions or helpful tips or the like?

I've tried Melatonin and have only taken it twice in the past week, and to be honest I can't really feel that much of a difference when I take it. I've taken about 0.75 mg and 1.5 mg doses.

I don't want to go into sleep aids or any of that stuff.