Day 5 blastocyst transfer

I was scheduled to have a Day 3 embryo transfer on Friday. The nurse called in the morning and told me all five embryos were still alive and looked healthy, so the doctor wanted to push the transfer until Sunday...a Day 5 transfer. I felt elated and surprised hearing this. From what I've read, it's quite good if it's possible to push the transfer until Day 5, because any blastocyst that survives that long in a Petri dish has a good shot of making it in the womb. And Day 5 is when a blastocyst would be in the uterus during a natural conception, because on Day 3 the little guy is usually still in the fallopian tube. So a Day 5 transfer more closely mirrors natural conception.

There's a chance all five could be dead when they open the incubator tomorrow. But it's my believe that if they'd transferred two into my uterus on Day 3 they probably wouldn't have made it, either, and I can't stand the thought of thinking I'm pregnant for two weeks (again) and then finding out I'm not (yet again.)