I had three Ds and three Cs on my transcript, a fact which came up in every single interview I had. The only interview where it wasn't an actual point of conversation was ISU (and I still brought it up as an answer to "Tell us about a time you failed at a goal"). Outside of that, I had almost entirely As.
I just took the complete honesty route. While none of the Ds and only two of the Cs were in pre-req/science classes (started out wanting to do something completely different, hated it, and my GPA definitely showed that), I fully admitted that I wasn't quite ready to handle college-level material at the time and my study methods were beyond sub-par. I did, however, also point towards my science and last 45 hours GPA, which included a semester of physics 1, organic 2, epidemiology, molecular cell biology, and microbiology alongside work, shadowing, and research, where I managed to finish with a 4.0, as evidence that I now felt that I was prepared to handle a heavy science-based curriculum. I also utilized the Expalantation Statement and basically wrote the same thing, albeit more eloquently. Schools seemed pleased with this, and evidently it worked -- zero rejections.
In your case, I also believe that honesty is the best policy. Is the D in physics your only really bad grade? If so, I sincerely doubt that it will significantly impact your chances provided that you can pull an A from the retake and you're GPAs are solid otherwise. I can certainly understand why a situation like yours (depression, moving away, etc.) could lead to an unusually poor grade. It happens. And, to be entirely truthful, I think that the explanation you gave upthread is sufficient. It isn't as if you're going the route of blaming something other than yourself. You are taking responsibility for a mistake you made, you learned from it, and you continued onward, which is an important trait for a medical professional to have and it demonstrates humility on your part, as well.
You could also use the Explanation Statement to state all of this, if you'd like. I know there are people who frown upon using it to explain, say, one or two or even three Cs. But for a D in a pre-req, it might be worth it, especially if you can take a similar approach to mine and follow it up with mounds of evidence about how this was just one small blotch on an otherwise competitive application (be that pointing towards a high last 45 hours GPA, giving an example of a previous semester where you achieved a very high GPA while juggling a lot, or anything similar to that).
Simply admitting that you did "drop the ball" rather than pinning blame on other things sometimes is the best route to take.
