Well, there's a happy update to this story. It wasn't maternity leave missing from my check. Instead, they had me listed at 2/3 time for some reason. I'm on my way to pick up a check. (I'm shocked that it only took them two days to get the check written.) We're still not in great shape with only one income, but at least this isn't a total disaster.
Great news that they got it figured out and were able to cut you a check right away. I'm sure that was a relief.