First of all, I can’t tell you how unrealistic it is to always expect to get straight A’s. Secondly, it’s not worth it.
I was six the first time I went to counseling because I misspelled the word “scissors” on a spelling quiz. I was inconsolable for weeks. That mentality led well into high school and college where I beat myself up repeatedly for “failing.” I would argue with professors about grades and, in hindsight, just embarrassed myself. Now, three years out of college and seven out of high school, I look back and none of that really mattered. Sure, grades are important for getting into schools or honors societies and potentially eventually careers, but it’s seriously not worth sacrificing your mental health for. In the end, your grades are just a numerical representation of your ability to perform, not a qualitative representation of your intelligence. The latter is undoubtedly more important in the long-run. Your character is far more important than your grades and will have a much larger impact than a an arbitrary number representing your GPA.
So, my advice would be don’t always stress about making A’s. Still do your best, always, but also don’t forget to consider the better aspects about yourself that school and grades cannot teach or assess.