I have extremely bad grades I know. I suffer from clinical depression and had an extremely bad battle with it during 9th and 10th grades and slowly got better.
That is only one way of weighting and may not be the way that your high school weights their grades. At our high school each individual numeric grade has a different weighted value based upon the level of the class. . E.g., a 100 in an AP course is a 5.5, but a 100 in an Honors course is a 4.8, a 100 in an Accelerated course is a 4.0 and an 100 in an Academic course is a 3.7. Just making these numbers up but this is effectively how our school calculates weighting.
For our HS the weight/value was broken down further than A=4. For instance, if your actual grade for class was 93 it was a 4.0 but 96 average was given 4.5, etc. Your guidance office or student handbook should tell you how your school figures GPA.