Shouldn't be, but can be. I would think that your other tests would reveal that, like AMH and FSH. Even so, you've got a good egg in there. It just may take a lot (even possibly too much) to get to it.
I was at SG too. I'd say they are top notch in terms of freezing standards and lab skill, so shouldn't be them. Did the embryo that resulted in your fresh cycle success look brilliant (A quality?) or was it iffy as well?
Yes, take a break and breath and rest and reassess. Best wishes.