I hope you don't mind me piping in here to try and offer a little hope. My clinic graded embryos a 1,2, or 3 as well but doesn't use letters, although they should because the way they described them would have made more sense. I transferred three embryos and was told they were all grade 2. Two of them just barely squeaked by as a grade 2 and were as bad off as they could be and yet still get that grade. The other was a middle of the road grade 2.
In the end we had two implant and one is still going strong, at least as of a week ago.
I felt like you and was so distraught. We were also told that there was an egg quality issue based on how terrible my embryos looked. I've got my FX that everything is just fine and you get an awesome surprise in a couple weeks!