I just wanted to mention for you, and anyone else interviewing, this is probably going to happen more often now. I interviewed around this time last year and I don't know of anyone that I interviewed with that was accepted immediately. It's getting towards the end of the interview season and so outright acceptances are going to start to peter out.
HOWEVER, all of those people (4, in fact) that were in my interview group that were wait listed are now in my class.
The wait list was very mobile last year. I was second quartile and I was accepted at the end of May, which still left 2 months for the other 2 quartiles.
Tldr; I've said it before, but I'll reiterate because the wait list struggle is real-- All is not lost.