Hey Jellybean1029.
It looks like what you've encountered is the beginnings of 'burn out', which is very typical in Year 12. The stress and work of VCE makes it not just a rigorous race to be the best, but an endurance run over the course of the year. Fortunately, there's some tips out there that can help.
Make sure you get your R&RDon't force yourself to work constantly and at times where your mind can't handle it. As humans, you can't work 24/7 without some repercussions. This includes sleep, resting and taking breaks here and there in long study sessions. You need a good mental state more than anything in Year 12. You wont survive if you can't chill once in a while. Lower your guard down and catch a break. You'll be much more motivated after you've balanced life outside school and VCE.
ExerciseIn the same vein as above, exercise can help your mind recharge and keeps you active whilst you're at it. It'll kill two birds with the one stone. Lots of Year 12s make the stupid mistake of becoming lazy in taking care of their health first (myself included once upon a time) and wind up sick. Might as well do that evening run ... and not to the local McDonald's!
Setting GoalsYou know one thing that can motivate you? Goals and inspirational quotes. I remember in Year 12, I had my usual quote: "You can change the past, but you can always change the future." stuck to the inside of my locker door. When I lost all motivation in my trial exams and even in my real ones, seeing this gave me energy. It's a super quick and easy solution that will cost you a sheet of paper, a little ink and 5 minutes of your precious time. All you have to do is write your goals and/ or your favourite quotes and put it somewhere you'll think you'll need it.
Clear your mindJust before you go to bed or just after you wake up, you're likely not doing anything much. Use 5 minutes of this time everyday to clear your mind. Try not to think about anything and just lie there with a blank mind. When you're ready, sort out mentally,on paper or electronically, what you need to get done today/ the next day. It'll recharge your body and help you stay organised. If that doesn't work and you have a lot on your mind still, take another 5 minutes to jot down everything you're thinking of or need to do, then organise your scribbles into a more orderly to do list/ timetable.
SleepLoss of energy is usually caused by exhaustion and sleep deprivation. If you know this is your root cause of your problems, try to do something about it. (I should probably listen to my own advice here.) It's not going to help if you can't concentrate in class and whenever you've dedicated your study time.
Talk to someone or watch something inspirationalTalk to your friends, your classmates, your teachers, parents or anyone you trust. Someone probably will have some great advice on motivation and their goals or strategies to deal with lack of it. They'll be your best bet to rekindle the fire within. If that plan fails, you still have the internet at large to find inspirational videos. It's not just for funny cat memes! I really like deep and meaningful ones like
this to help me get into the mood. There are plenty just like that.
Change monotonyJust like the tips from other AN users, make things different and spice things up! Monotony is boring. Go study with friends, study at the local library or listen to baroque music instead of dead silence as you study. Experimentation might just help you find a new, better way to study.
Limit DistractionsYou're not going to get things done if you're distracted. Place your phone on the other side of the house, turn off your internet connections if you don't need it and leave the pet (if you have one) outside your room when you're studying. Use ColdTurkey or other similar software to ban you from using the internet if sheer willpower doesn't hold you down.