You've said that you have test anxiety and that you are stressing about it, and seem to think that this is at least part of what's causing you to make silly mistakes. Goro is right: go to the counseling center. They will teach you tools and strategies to minimize your anxiety on test day. It sounds dumb, but they are evidence based and effective for many people.
If you want to be a doctor, over the next decade or so you will be taking too many high stakes exams to count. Build the skills you need to do well now, rather than waiting until test anxiety negatively affects your academics/career.
