I'm also a Catholic, and my problems with the moral implications of creating embryos that will be destroyed was one of my reasons for going for embryonic adoption - this feeling that I hadn't chosen to make these embryos, they would be sitting in a freezer regardless of my actions, all I was doing was offering the chance for life to them.
But also I'm a science graduate and a veterinary surgeon. I have a certain ambivalence towards the state of an unimplanted embryo. I can't give them quite the same status in my mind as an implanted one that has started to grow. In my mind, an acorn is not an oak tree, it is the potential of an oak tree, and in a similar way, an unimplanted embryo is the potential of a human life but not yet a human life - worthy of respect in its own right, but not the same. We really have no idea at what point ensoulment takes place - if such a term can even be used, and so all we can do is give a wide margin for error. A baby that can survive outside the womb is a human life. If an unimplanted embryo in the womb splits and implants as two identical twins, they are two people - two lives, two souls. So the best evidence we have at present, and God alone knows the truth, is that it happens at some point between implantation and birth. Beyond that, all we have is our own conscience to guide us, and as I said in another thread, trust in the infinite love and mercy of God.
God bless you