I'm usually a descriptivist, but "literally" is a hill I'll die on. It's not as much changing meaning as losing one altogether, and it's such a useful word with no appropriate replacement lining up.

"I laughed so much I peed myself" -> an idiom that means I laughed a lot

"I laughed so much I literally peed myself" -> with original definition of "literally", this means that I laughed so much that urine left my bladder and soaked my pants. With the new excuse of a definition, it means the exact same thing as the first sentence, just with more "hey, duuude, like, I was saying, like" energy. What if I did literally pee my pants and want to share the great news? I literally cannot because of people misusing that word!