Can someone lift up the spirit and give me a few words please. The problem is I always tend to do every single question in the book, but when I get even one wrong I always feel something at the back of my brain telling me im not good enough, and that specific question WILL pop up on the exam and I wont be able to do it. Its so stressful and I cant help but think about it. Even when I dont get something wrong, I still feel this way, that im not good enough and that all my hard work will not pay off. I dont know, why does this happen 
Well at least you're making the effort now to get these sort of questions out of the way so when it comes to exam time, you'll be blitzing compared to the rest of the state

Just remember that you have plenty of time to rectify anything that you don't understand

Alternatively, I've seen that you've been doing lots of Maths questions over these holidays... why not spread the workload around and dedicate time equally towards other subjects too (that way your mind is refreshed and you may see things that you didn't before [on another note, proofs are things that you either get straight away or take time to go through so don't be too disheartened yet]

)