LonghornXP-
Did it ever occur to you that possibly it was not the subject you had problems with but maybe it was the quality of the instruction, or the workload, task loading, you were under at the time and maybe were not able to dedicate adequate time for the material?
Personally, I found that those courses I had great trouble learning could be objectively pinned down to outside influences. eg. I wanted to learn German as my foreign language in HS. I had 4 weeks of introductory German in Jr HS along with a half dozen others during the year. Due to being a military brat, I was transferred to another state and the new HS took my transcripts and mistakenly put me into a second year German class. On day one, all they spoke in class was German and I was not permitted to explain in English to the teacher, who was also a disciplinarian gay man with a whip he cracked on the desk when you tried to say anything in English. So I puilled a clean F in the first grading period before the idiot guidance counselor listened to my mother who got me transferred to German 1. Now if that was a brilliant move, I know you are laughing at this by now with empathy. I was 6 weeks behind the students in German 1. And to add salt into the wound, I had the same teacher! By the 3rd grading period I managed to squeeze out a D but failed German for my Freshman year. So what did I take for next year, No German as I had to dump this Nazi gay freak of a teacher and selected Latin. While the guidance counselor was against this because I did so poorly in German, I managed to get straight A's in Latin and continued to take 3 years of it. The benefit was I also improved my English grades to straight A's as well. Believe it or not, I wanted to be a chemical engineer but could only squeeze B's and C's in math so the math was a struggle for me too. In retrospect, I have to say, math was a huge time consumer and a struggle to complete the workload, participate in sports and play trumpet in the band and the local symphony Orchestra. Back then I was a pretty good trumpet player.
Point being, when you are suffering a subject, don't blame yourself. Take an objective look at the time management of your life and prioritize what needs more of your time.