Right here.
I agree with all of the above sentiments. A failure in a clerkship is a serious issue. At most schools, less than 2-3% of students fail their clerkships, so this clearly is a "red flag". As other have mentioned, sometimes the failure is due to a shelf exam score -- in that case, repeating the exam and getting a good score, and taking Step 2 early (and doing well) will go a long way towards reassuring programs about your skills.
If you failed due to clinical evaluations, that's more serious. I certainly understand your above statements about personal / family matters that impacted your performance. You are certainly entitled to your privacy. However, Program Directors are going to want to be sure of two things: 1) that the issue that caused your problem is completely resolved, and 2) you are not likely to "fall apart" again when a stressful family situation occurs during your residency.
The best way that you can do this is to be 100% honest, and put thye whole story in your application. I agree with the above poster that your PS tends to be the best place to put this. I have seen some applicants explain problems like this mixed into their PS, and some write a split PS -- first an explanation of their problem, then a line, then their "real" PS. Doesn't matter either way.
Some programs will throw your application in the trash without further review, and there is nothing you can do about that but apply broadly. That being said, many good programs will likely still interview you if you are honest and up front. If you hide behind "personal, family problem" programs will assume the worst.