C+ in Math

Hi, so I'm a junior and I plan to apply to T50 colleges in my senior year. However, I've been struggling in math this semester and currently have a C+. There are a few weeks to get the grade up to a B-, but in the case that it doesn't increase, how will this impact my college admissions? I'm particularly worried since this is during my junior year as opposed to your sophomore or freshmen year, where colleges expect you to make mistakes in academics and such. For reference, I am applying as pre-med major in bio (so class is not related to major) and want to get into colleges such as unc chapel hill, case western, and the university of rochester. Additionally, the rest of my grades throughout my HS career are either As or Bs (3.8 gpa)