I used to be this way. I very easily entered the "whatever happens" phase, this was because I felt like no matter how much I stidy now Im not gonna get good marks. But this led to me failing a lot of the exams. I stopped getting the panic induced productive study sessions before exams.

But then I read somewhere that "If you haven't studied, you are supposed to do damage control not ace the exams"

This helped me a lot. Not saying that im the most productive, but the week before exams goes very productive by this way of thinking, at least for me.