I;m in my senior year and got a B in AP Calculus and AP Stats (math is my worst subject). I wanna know how much this will hurt my chances of getting into UCSD, UCLA, UWashington, UMiami, and Pepperdine. My dream schools are Vanderbilt and Dartmouth, but I doubt I’ll get accepted.
My GPA before senior year started was 4.195 (4.2) , and SAT was 1400.
I also got 2 Bs my sophomore year in Chemistry and Alegebra 2
I’m super stressed out now because I feel like my chances of getting into UCSD is close to none 
UC’s will not consider your Senior grades for admission purposes. Your Senior grades help maintain your provisional admission if accepted. For UCSD, you want to maintain a 3.0 Weighted GPA for Senior year, no D’s or F’s. For UCLA, you need to maintain a 3.0 Unweighted GPA and no more than 2 C’s, no D’s or F’s. I cannot comment on the other schools are on your but if you have to send in Mid-year Senior grades, they will have a negative impact on your chances.