Thanks, everyone, for wishing Maggie well.
Maggie continued to get worse through the day on SUnday. I ended up trailering her to Pioneer Equine Hosptital, 85 miles away. She had colic surgery that revealed a torsion with a lot of gas that was probably due to an infection. The cut her intestine to let out the gas. She came out of surgery fine but is not out of the woods yet.
I feel very, very old.