Make don't sense words

I'm not good with linear thinking. I tend to see things in a holistic way rather than broken into separate parts. My mother thinks I might have a mild learning disability. Blood, sweat and tears have gone into every paper I have ever handed in. The comment I get most? "great ideas" "good reading of the text" Interesting and original interpretation" and Oh Yeah ,
"watch your spelling and grammar" "proofread more carefully" "many small grammatical mistakes"
Good ideas - bad construction
I do proofread-
What happens is -I don't see my mistakes. I read for what I meant to write -not what is on the paper. This is becoming critical as I am taking a 200 level grammar course this semester and I am not doing well. It is mind boggling how incompetent this class makes me feel.
Form, Function, and Position - My mind is in a fog of meaningless designations that don't relate to any sense of words as a form of communication.
The textbook gives unclear examples, while my classmates waste time with pointless questions.
When we are given examples, I think "I understand" -then we are given quizzes, and I stare at the page unable to answer anything right. What is more, the quiz was open book!
The problem is, when I read the example sentences that the textbook and the instructor gives, I can't get past the Meaning of the words to see the bones of the function of the words. I read for meaning -not structure. Sigh