The conceptual stuff was never a problem, and I think I got into the habit of going "oh I understand how this works" and never took the time to memorize any of the the details (and then I'd run out of time trying to reconstruct formulas on tests and fail them...). If I had actually taken the time to study (since that was effectively the only class I ever would have needed to study for) I'd have been a lot better off.
Also anything applied is about a million times easier (otherwise I can't identify what the end product should look like). Right now I'm in college taking "Applied Calculus" for business/social science majors, and it's way better. So there might be hope for you yet.