I've spent the last hour Googling, and am choosing to believe the nurse when she said this isn't a bad thing. At least we've got four embryos in early blastocyst stage. That's a good thing. I'm going to hold on to that and not worry about egg quality or why all four of them are a day behind where they'd like them to be.
At least this way I'll be able to take down the Christmas tree today.
That should keep me busy for at least half an hour or so. Sigh.