So first, it's important to take a step back and chill out when it comes to Chemistry. It's often credited as the hardest A-Level subject, so it's completely fine that you aren't doing as well as intended. I did Chemistry and found it very confusing at times, and I was often underachieving in homeworks, mocks etc.
I found that youtube videos were a good source for revision, as well as flow charts showing different reactions, their colour changes, and other useful information about them. Also, remember to do loads, and I mean LOADS, of past exam questions, as similar questions will often pop up through the years. Closer to the actual exams, I liked to blutac pieces of paper around my room with various mechanisms, reactions etc.