that is not fat. that is actually quite tiny.
secondly, have you considered ADHD or an undiagnoses LD? also, when you say that they referance other classes that you skipped, it is quite possible that you knew enough to test out of it on the standardized assessment, when in reality, you have some holes. that has happened to friends i know, and it makes things like math, language, and science really hard because those things are cumulative (build on one another). have u considered tutoring?