D- or F+ . . .is there a difference?
The thing is one grade will not keep you out. A pattern of D- grades will definitely keep you out of medical school.
It is not so much the mistakes in medicine, and the path there to, that are so tragic. It is the way people handle mistakes that will ultimately present a person's capacity to become a good physician.
My university did not have this "take it again option". My vote, is that you accept that this happened to you and you don't let it happen again - especially since you don't seem to like how it feels. Regardless of the biggest blemish on your application, you must know that someone else has a larger blemish than you.
That's my opinion, PM me and I will send you an address where you can mail me a donation. Good luck, you too can rise above this.