GPA's and intelligence are not synonymous; you should never allow that number to define you. There are several aspects, those that are in your control and those that are out of your control, that contribute to meeting the criteria to earn a certain letter grade. Sometimes, you push yourself to new levels and work harder than you ever have before and that amount of energy is still not enough to achieve that high grade like you had intended. Sometimes, you do everything right, but still end up only a couple points away from the A. Sometimes, your professor is ignorant to the fact that you personally progressed through the class, and is hung up on you not quite meeting "their standards," so you get a low course final. Sometimes, you only halfheartedly designate any time towards a class or assignment, yet still end up with one of the top grades in the class. Sometimes, you know deep down inside that the effort you put into your final product should not be deemed as worthy as your teacher is claiming it to be, but you'll take the high grade and compliments anyways. My point is, if grades are not always earned, and earned grades are not always given. then why do we allow ourselves to get so caught up in the stress of striving for that perfect test score or straight A's for the semester?
Of course it is great to set the bar high and stay focused, determined, and invigorated in terms of aspiring to achieve your goals; however, it is also important to understand that it will not be the end of the world if you don't. You must be able to accept that as long as you tried your best and can admit to acknowledging that there was at least one aspect of personal growth as a result from taking a class, then that is more valuable than a simple letter grade.
Think to yourself about one of the toughest classes you have ever taken; now you may remember the failed quizzes or poor paper grades, but the life lessons, course details, insight from that specific professor, and the journey of enduring the course in general are actually the aspects that you can recall the most vividly. Those are the aspects that have helped shape you into the individual that you are today; not the final letter grade that was typed onto a transcript on the last day of the semester and then totally forgotten about the very next day.
Furthermore, grades are not always clear reflections of "learning." Each individual has their own definition of what this ambiguous term encompasses. What does it actually mean to "learn" something, and how can teachers determine if you have truly "learned" a concept? Another challenging point that is necessary to bring up is that every person had a different learning style that is best suited for them. While some teachers try to filter in alternative learning techniques to include all learning styles, some teachers do not. Then it becomes the student's responsibility, understandably, to make changes to adhere to the classroom setting which can work out for some students. For those students that can't learn the specific way that the material is being taught, then there is more of a chance of their final grades being at stake. You cannot punish yourself because you lack the ability to learn a certain way either all together or quickly as long as you gave your best effort; the grade you receive, despite the circumstances, is the grade that you are stuck with, and you cannot let one grade negatively impact your self-esteem.
Additionally, grading scales differ from school to school. There are different amounts of attention, worth ethic, focus, and drive depending on how far you must push to fall into a certain range. For some schools, the minimum percentage for an A is 90, while for others the minimum percentage is a 93 or 95. How can a GPA be taken so seriously when schools are not operating on a universal grading scale?
You can still learn valuable lessons and interesting information even if you don't perform very well in a certain course. You can still be an active learner even if you have to retake a class. You can still like a class even if you failed the test you took last week. You are still an intelligent human being even if your GPA isn't perfect.
However, be sure that you do not make getting low marks a habit, but also be sure to allow yourself to believe in redemption. As long as you accept and try to understand the situation that you are in, then nothing else matters.
Grades are meaningless until you burden yourself by associating these mere letters in the alphabet an unnecessary amount of imaginary weight.