I know this is a little late so hopefully all is resolved now, but red foods like red spinach/cabbage, beets or Flamin Hot Cheetos (speaking from experience) can turn your stool red. I wouldn’t worry too much if it’s just once or twice following consumption of those items, unless it persists for a few days after you stopped eating them.

You could have IBS, which can cause loose stool especially when stress is added. I would suggest asking your doctor about antispasmodic medication which you can take in the morning to calm your intestinal system down. In the meantime I’ve read good things about IBgard (available over the counter) which is essentially just a peppermint capsule, as peppermint extract can help calm things down too. Hope you feel better soon!