The Help star, who is currently dating British actor Andrew Garfield, was just 14 years old when her then-boyfriend ended their teenage romance, leaving her feeling physically sick.
She tells Interview magazine, "I was crawling on the floor. I remember throwing up. Like, within the hour (of the break-up). I remember being on the floor... I have never felt anything quite like that. It was so visceral. It's like someone has killed you and you have to live through it and watch it happen... It was awful."
Stone previously drew from the agonising split to inspire her performances, but admits she has since moved on.
She adds, "You heal yourself. It's weird when you can't make yourself cry with the same things anymore."