Jenni,
Well, you were right. There are no ATL>SXM flights on Thursdays now. They went ahead and changed our itinerary so that we had a 26 hour layover in Atlanta. Um, no. But there is an option(!), a 20-something hour layover in San Juan. Um, double no.
Enough is enough. It's time to cancel and find something else. I can't take this uncertainty, I have enough of that in real life.