Hi Chris, I'm so sorry to hear that you're stressed during your exams. Exam season is a super stressful time for everyone but there are a few things that you can do to help you feel relaxed and focused. As a fairly recent graduate I recall feeling especially anxious when I felt underprepared in an area/ subtopic of my upcoming exams. Sometimes reviewing the areas that you are least confident in can dissipate stress. I felt most content when solving the thing that was causing me exam-stress in the first place. Jumping up and down for five minutes or running is a really good way to get rid of the jitteriness if you experience that though :) An acute kind of exam-stress is also often induced by an intense awareness of time running out. At these points you just need to take a breath and remind yourself that you're human and are doing the best you possibly can. Taking a break to do something you love or to just help you switch-off can be very refreshing to your nervous system. Some studies say that we can only focus very intensely on one thing for 45 minutes. Good luck! :D
Pick a time of day for about an hour when you do nothing but things you enjoy. This will give your mind time to relax and store the information.