Day 7 Blastocyst - any success stories?

Hi All,
My husband & I have not long returned from the US after traveling from Australia for our first fresh cycle/transfer.
We had one embryo transferred - Day 5, graded AA, and we were given a 90% chance of a successful pregnancy resulting.
Unfortunately it failed to implant and my blood results came back negative, so back to square one.
We have one frozen embryo remaining - however this didn't expand to blastocyst stage until Day 7 I believe. And has been graded BC and we've been told 50-60% chance of a successful pregnancy resulting.
Half of my brain is saying "what if"... and maybe we nee to exhaust all options and roll the dice with this last remaining frozen embryo (as a whole new fresh cycle isn't financially or logistically viable for us right now).
But the other part of me is saying "are you crazy?!?"... a day-5 AA with 90% chance didn't work! So why on earth would a day-7 BC?!.
Huge risk making the journey over to the US again... with such low odds.
Feeling a bit conflicted.

Sorry to hear your embryo didn't stick, I wish you all the best with whatever you decide. Unfortunately I don't know much about the chances with transferring the other one, but there is always hope. I completely understand your dilemma, good luck with whatever you decide