It can be done, I promise you. I attended pharmacy school and graduated in 1988. Back then prepharmacy required calculus, organic chemistry, calculus, physics, microbiology, and more. Pharmacy school had subjects like biochemistry, pathophysiology, pharmacology, compounding, pharmacokinetics, pharmacy math, pharmacy law, on and on.
In those days, I knew something was wrong with me, I even went to see counselors at school, nobody knew what it was. Since something was wrong, I didn't think I could make it in this world without some kind of degree. Pharmacy school is rough, a lot of memorization. My ability to concentrate was pretty poor, when I would sit and try to study, my mind had a tendency to wander. I remember devising ways to help study. I would tape lectures, then type them when I got home. I remember studying pharmacology, I would draw anatomical diagrams, and then routing various biochemical pathways, ALL IN DIFFERENT COLORS.
I remember studying late at night every night, and on weekends, I would start at 6am Saturday morning. I would study to the best of my ability until about midnight, then do the same on Sunday.
I believe things would be different now. The study of PTSD has progressed light years ahead of where it was. In addition, dr's can prescribe meds that can help, and most importantly, the counseling center at your college can work with you on developing good, and constructive study habits.
You CAN do this!!!