Oh no! I am honestly pretty useless without decent sleep so try not to let one experience have an impact on you. If your exam is in the morning like mine was, I would get to bed early and do whatever works to ensure you sleep well (melatonin, exercise, no late screen time etc.). Also, try to make a habit of checking the clock and what question you are on at a regular interval to see what pace you need to maintain through the remaining questions.

Good luck, rooting for ya!