Of course you can! You have many more SACS to go, and try to do the best that you can! Be confident! I've did really bad in Methods last year because I was not confident, and convinced myself that these results were expected.....
But this year... I tried really really hard for my first SAC and got good score I was really happy with. Be mindful that SAC scores are not really important, its about your Ranking.
There's not much you can do now, you can't change your scores for the SACS that you have already done, but the scores that you obtain in future SACS, and exams at the end of the year are all dependant on how hard you work now. YOU NEED TO WORK HARD, THERE IS NO SHORTCUT! Everyone with really high scores have worked tremendously hard. Don't think that you can just fluke a score over 90+ without hardly any effort.
I suggest getting into the routine of regular study, and KEEP UP WITH ALL YOUR WORK cause I know the workload can be really overwhelming. If you can try work ahead at your own comfortable pace, pay attention in classes, use teachers to your advantage! Expose yourself to many many questions from different resources, write more essays (get your teachers to mark them/ post them up on atarnotes. I've seen the English board and many people (Brenden in particular) give amazing and detailed feedback!. Post up questions on AtarNotes, theres a very supportive and brilliant community who are definitely willing to help. The more work you do, the more you feel confident and the more you will inevitably improve!
How bad do you want this? GIVE IT YOUR ALL AND DON'T SETTLE FOR ANYTHING LESS! DONT SECOND GUESS YOURSELF.
If you truly commit, you will succeed beyond what you ever thought was even possible!
It's all in your hands! Stop moping around and GET TO IT!
