That doesn't seem to be one of the reactions one could have. Not saying it's impossible.
However, FWIW, I doubt it was the epsom salt.
Epsom salt baths, and foot soaks are usually very relaxing, between the hot water, and the magnesium. There are stories from mothers with autistic children about how it relaxes the kids.
Maybe it was just one of those 24 hour bugs?
BTW, epsom salts are a great exfoliant. Put some in a bowl and add just a very little bit of oil. Can be body oil, or even just olive, avocado oil. Should be the consistency of wet sand.
After your body gets all warm and hydrated in the shower, turn off the water for a bit, scoop up handfuls and rub all over. Feels marvelous.
Becareful though since the floor of the tub may become slippery. Clean the tub afterwards.