ACC to AAA

I just got my last set of predicted grades for year 13 and im currently on A (psych) C (maths) C (Chemistry).
I actually thought I was going to do well in maths but I dont know what happened, I was just losing marks out of thin air.
Chemistry, my teacher is constantly using OCR exam questions instead of AQA questions (my exam board) so I feel that it is causing me to have a massive decrease in my grades because of this. It is utterly upsetting, I dont know what to do but I really want to get AAA in the summer.
Anyone gone from those grades to A/a*s lmk also my exam boards for maths is AQA and Chemistry is AQA so if you have any specific advice it would be so helpful!!!
Do respond really quickly. Thanks.

I don't do Chemistry but I do Maths (Edexcel) so maybe I can help.
The key with maths is practice but first you need to make sure you have a good understanding of all the topics. I don't know about AQA textbooks but try the review exercises or just flick through and see if there is anything you think you are unsure on. You can then use the textbook or online resources my favourite being TL maths but there is also dr. frost and others. There is also mr. bicen maths who does these everything you need to do videos which are nice and quick and you could watch them and see what you need to work on. He may be specific to edexcel though so hopefully someone actually doing AQA could help there.
When you are sured up on all your content then just do paper after paper and you will learn from your mistakes. It won't happen over night but e.g. integration comes from practice.
There is a really good TL maths resource actually https://sites.google.com/view/tlmaths/home/a-level-maths/bumper-book-of-integrals which might be helpful for practising things like that.
From those practice papers target the topics you fell short on and you will also find yourself becoming quicker which will help with having checking time.
Good luck and if you have any questions feel free to ask.

I just got my last set of predicted grades for year 13 and im currently on A (psych) C (maths) C (Chemistry).
I actually thought I was going to do well in maths but I dont know what happened, I was just losing marks out of thin air.
Chemistry, my teacher is constantly using OCR exam questions instead of AQA questions (my exam board) so I feel that it is causing me to have a massive decrease in my grades because of this. It is utterly upsetting, I dont know what to do but I really want to get AAA in the summer.
Anyone gone from those grades to A/a*s lmk also my exam boards for maths is AQA and Chemistry is AQA so if you have any specific advice it would be so helpful!!!
Do respond really quickly. Thanks.