Man, I remember my Prelims... and being quite depressed actually.
Like, I mean, I was failing 2-u maths and Chemistry hardcore and was just passing History and Economics.
Then Year 12 came along and I dropped Chemistry and went down to General Maths.
I now rank 1st in Gen. maths, 2nd in Music, 2nd in ext english 1, 3rd in History, 3rd in economics and 5th in Adv. English.
There is life after Year 11. Remember that can do it and that Year 11 is rarely indicative
of how well (or how poorly) you're going to go in Year 12. My advice: study consistently, and don't stress.
Don't ever decide not to study though. (that's why I failed two of my subjects last year!)
You'll achieve if you desire.
xD