Your brain works even when you're sleeping Maxine, otherwise you'd be dead and gone. As for working harder, there are resources online and books that give help and advice on study techniques, essay writing and how to pass exams etc. Everyone feels like this at one time or another, even at work and they all need to use resources to work harder or be successful. That's why they're available as they do work.
The brain can change and grow. Through neural plasticity if can create new neural pathways. You just have to work at the right exercises. My sons has auditory processing disorder, but through different exercises we have been able to slowly help him create new pathways through the brain that make him better able to work with it.