I'm completely demotivated to work; what can I do?

I'm two years before heading off to university, but I have no motivation to learn the things that are being taught at college. I chose to study the subjects that I thought I would enjoy, but sadly this isn't true. I'm assuming that if I had made other choices for subjects, I'd be in a similar problem. Maths is one of the subjects I'm studying, and although I enjoy maths itself, I'm not enjoying what I learn in school. I can't be motivated to put the work in, so that I can get good results at the end of the year. I spend my free time programming or researching instead, but I can't continue doing this if I want to get the A-levels I need to enter a half-decent university.

Are there any ways by which I could motivate myself to study more?