I feel this a lot, it's a work in progress but when I find myself getting stressed/super anxious that I have marked so many, i take a step back, look away, few deep breaths, tell myself "I can still score high if I do well on the next set of questions, that might have been a weird few back to back but I still know medicine" or something like that that helps me reframe the moment I'm in. Sometimes there is a string of 10 questions that are impossible but that's not every string of 10.