No, you are not too stupid. I am completely math-inept. I literally cannot do basic subtraction in my head without "writing it down" in my head. I got a B in College Algebra, a B in Precalc, an A- in Calc 1, and an A- in Calc 2. You know why? Because I worked my *** off and didn't give up. You literally must do every single practice problem, and talk to your professor. Most math professors love teaching you math any time of day. Oh, and a MUST for any math course is to have a good professor. I know for a fact, besides my work ethic in the course, my excellent professor in Calc 2 saved me...he actually made me enjoy it!
Good luck!