No need to freak out. Just be diligent about checking in AT 24 hours, and you'll be fine.
I was recently on a flight that included something like 56 through passengers -- a lot, in my experience. Even after they offloaded the terminating passengers, and the through passengers did the seat-shuffle, there were plenty of rows available. (Think about it this way. If there are 23 rows on the aircraft, that makes 46 "half-rows" of three seats. Even with 56 through passengers, and even if every SINGLE half-row had a passenger in it, (unlikely, as many of those 56 were families or groups, and therefore grouping together,) 30 of the half-rows would still have two seats available together.)
How many are in your party?
ETA: My best guess, looking at the timetable, is that that flight comes from BWI (Baltimore.) There's no published BWI-PVD-MCO connection on the SW site; someone might be able to force one but I have no idea why they would do that when they could take a n/s flight in half the time. There are 9 n/s flights from BWI-MCO that day. Excepting a very odd hiccup, and presuming my BWI deduction is correct, there will be no through passengers on that flight.
FWIW, the flight continues on to FLL (Ft Lauderdale) after MCO.
Hope that helps.