Yeah, it's a mess. But a non-friggin'-stop flight, and I was the only one on the flight whose bag didn't turn up. I watched the bag go through the scanner after which it got loaded and wheeled off with the rest of its "mates".
It didn't make it on the BCN flight tonight. That they know, which makes me think the tag is torn off, since they have no idea where it is, except that it wasn't on the next-day (today's) flight out of JFK.
Well, the odds were against you. Think about you were 1 in 200 something. What are the odds?
However, I would make sure you get DL to agree to reimburse you for reasonable needs over the next few days.
I had this happen a few years ago (on another carrier) and amazingly about 4 days later here comes the bag! no idea where it had been.