Don't bludge in Year 11 but you shouldn't over-work yourself either. As soon as your over-work yourself, you'll be too sick of school and too tired to do anything in Year 12.
Work as much as you need to, and although extra-cirricular activities are a good thing, don't do too many either.
...you should b happi dat ur doing well at school.!!!
but there are reasons for ppl disliking school..such as peers..teachers..etc
so..good luck! nd keep up ur good work!