If this possible outcome makes you sad why on earth would you remove a gravid female from the wild during breeding season? If it's only been a few days and there's no chance she came in contact with any foreign frog diseases, you can still put her back and let nature take its course.
Did you read the care sheet I linked to before? Are you ready and able to handle around 2000 eggs should you manage to get them to breed?
This is impossible as fertilization in Gray treefrogs (and nearly all other frogs) is external.