Bad grade in AP Calculus AB

My first semester of my junior year is over, but I received a D in AP Calculus. I’m not going to blame it one my teacher. She is super sweet, concise, very helpful and she is very respected teacher. However, I have noticed on my homework and exams that I make very stupid mistakes that I was never aware of or I forget what to do and this has definitely taken a toll on my grade. I’m not a slacker in that class. When I answer questions for exams, I literally write certain things that does not pertain to questions and often times forget that I wrote such things. I have taken all honors, AP, and dual enrollment courses throughout high school and I get mostly B’s with a couple of A’s and 2 C’s in terms of semester grades (3.3 UW GPA and 4.00 W GPA). I just don’t want my D in Calculus to have an affect on my college application. I’m not applying to any Ivy Leagues or top schools. I will most likely apply to colleges in the state of Florida (Florida State, Univ. of Central FL, FL Int’l Univ., Univ. South Florida, and a couple of state colleges such as Valencia College and Santa Fe) since they are within reason for me. I cannot retake the first semester since its an AP course and not a graduation requirement. I’ve done well in my previous math courses such as an A in Pre-Calc. Honors and Algebra 2 Honors, and a B in Geometry, but I’m not sure what is going on with AP Calc. I’ve always done relatively well in math since its one of my strongest subjects and the odd things is that I don’t find AP Calculus to be difficult. The material is very straight forward, but I keep making stupid mistakes that cost me tons of points on exams/assignments and I was never aware that I made these mistakes. I’ve been thinking about dropping the course, but I want to prove to colleges that I can be successful second semester and I am shooting for a 4 or higher on the AP Exam. Is it worth the risk? What would you do in this situation?