I had lots of embryo's as well and to get DD we had 1 fresh transfer and 3 FET's (2 embryo's transferred each FET) so all up 7 embryo's used for 1 baby and with the twins we had 2 FET's (of 2 embryo's each) 4 embryo's for 2 babies.

Has your Dr tested you for MTHFR, which if you have the gene can effect the embryo's ability to implant. If you google MTHFR you will find heaps of stuff, I know a lot of IVF'ers who have the gene but didn't know it and once tested and found out it was as simple as have daily asprin, although some have to have daily clexane injections.

MTHFR also can be a reason for multiple miscarriages.

I hope you find the answers soon and your next baby is not too far away.