Will 1 D in 2nd semester sophomore year hurt me a lot for college?

It all depends on your grades next year. Junior year is crucial, you really have to step up your game. Remeber that there are millions of other kids around the world taking just as many AP and honors classes as you. Another good idea, if you havent already done so, is to join as many clubs and extra cirricular activites as you can manage without affecting your grades. Colleges look for someone who can contribute something to their school other than just good grades. Do whatever you can to be as competetive as possible.