I'm in the same boat as you OP, I managed to quit the game before my GCSE exams and managed to get excellent gcse results, to be able to do what I want to do at A-Level (Chemistry, Biology, Physics, and maths) Which are all quite tough, and require a lot of hard work, however I have recently found myself back and even more addicted to this game than I was before, honestly right now its my christmas break and I am playing this game around 12 hours a day, maybe 7 when I decide to go out. I find the game 50% enjoyable and the other 50% is just a grind, so I'm really trying to get through all the fun bits of the game this break and hopefully it will give me incentive to quit when I'm done with all the fun stuff and gotten to the boring stuff.
Anyway goodluck to the both of us and honestly the reason I quit before my GCSE exams was when the EOC beta came out, and the jmods said it is a permanent update blabla, after finding out I hated it I quit asap, and now I actually like it once I came back to RS3.
I also used about 200m ingame cash to buy the gold premier membership package, = 1 year memb + some other features
This is not going to help me and I don't know why.. I would do something like that
Alas, goodluck friend