Would getting a C+ ruin my acceptance? PLEASE HELP?

So I just got into Vanderbilt last week on early decision, so therefore I am admitted and bound to that school. Now my report cards have largely been in the ballpark of four A's and two B's. This quarter I have four A's in my honors courses, a B+ in my AP, and I HAD a B+ in a very vigorous Spanish cl. I just got a test grade back that is ridiculously weighted at 40% of our grade at the moment (no we haven't taken midterms yet) and I received a 75 which is my worst grade by FAR. I had an 88 average going in and now I have an 80. Now I'm really scared because if I don't do well on all the rest of the upcoming ignments (including the looming and more than likely difficult midterm) I might get a C+. Do you think that this would devastate my acceptance even though I kept my other cles at a very high level? Please help!