Spells work, just not the ones to stop time, change gender, species, controlling the weather, etc.
As I've stated numerous times before, magic has its limitations and works within the realms of reason and logic. It can't be used to change your gender, race, species, etc. It can't be used to reach unimaginable odds. As practitioners of magic, we must first learn to accept and understand its limitations and its basics before we can truly begin practicing or understanding it.
My suggestion would be to learn better time management. Try to write out a schedule so that you have a block of time, say a few hours, to study everyday. It can be a little hard to get used to at first, but it pays off in the end. I do it all the time for my college courses.
When I first started college I did poorly my first semester because I used the same study methods as I did in high school. I studied whenever I felt like it, pretty much, and my grades suffered for it. I then set down and made a schedule so that I could better accommodate for study time. Trust me when I say, learning proper time management will do wonders for both studying and improving your grades.