What do you mean 'the third day of ovulation?' You ovulate ONE day. When the egg pops out of the ovary, that's ovulation. (And after that occurs, the egg lives less than a day.)
I wouldn't worry about this. If there WAS damage to the egg, it would probably just not be viable, and you wouldn't conceive this cycle. (Or would have an extremely early miscarriage -- so early you wouldn't even know you were pregnant.) But, unless the x-rays were of your abdomen, no radiation would have reached the egg anyway.
