try to stop listening to music if it distracts because there is not point in studying and listening to music if it distracts you. listen to music in your spare times or switch from rock to some kind of relaxation music or something.
:music::bomb::(
it depends on the school. some school allow this and some dont. but always remember that your preliminary stuff are base of HSC studies. so if you drop now, you will have heaps and heaps to catch up on and you already have missed out half the work. so.... i would suggest not changing right now...