I have gotten my first C in my undergraduate career, how does this affect me? Law school, careers, employment.

I know that sounds anal, but I am very upset. I am a good student and until now have maintained a 3.8–4.0 GPA. My hope is to one day get into an ivy league law/graduate school. Have any of you gotten a C and still done this? I have extensive extra curricular activities, does that help? I am so upset I feel sick.