Ok, I've got several friends who interviewed at Drexel last cycle, and several of them were outright post-interview rejected.
Now, these friends include one who is absolutely charming and one who is quiet but very kind and extremely smart (99th percentile MCAT score). I cannot imagine that either of these two people could be more qualified to go to medical school, or that they would have had bad interviews. I was definitely shocked when the reject letter arrived. Apparently, according to my one friend who did make it through, Drexel's ADCOM has some very finicky people on it and if you had the wrong person interviewing you, you're screwed.
I mean, this really isn't that far off from what I've heard about some of their profs (apparently one likes to get revenge whenever a student ticks him off?!) so all these post-int rejects aren't surprising from that standpoint. Of course, it sucks for you (especially since you are totally qualified). I don't know what you can do-they may be able to tell you why you got rejected, but reversing the decision probably isn't going to happen. Good luck with apps and hopefully you get in somewhere you like just as much, if not more.